Common Weakness Enumeration

CWE-601

Allowed

URL Redirection to Untrusted Site ('Open Redirect')

Abstraction: Base · Status: Draft

API response cwe.mitre.org

The web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a redirect.

2564 vulnerabilities reference this CWE, most recent first.

GHSA-R7P7-QR7P-2RRF

Vulnerability from github – Published: 2022-05-14 01:21 – Updated: 2023-10-31 20:17
VLAI
Summary
Symfony Open Redirect
Details

An issue was discovered in Symfony 2.7.x before 2.7.38, 2.8.x before 2.8.31, 3.2.x before 3.2.14, and 3.3.x before 3.3.13. DefaultAuthenticationSuccessHandler or DefaultAuthenticationFailureHandler takes the content of the _target_path parameter and generates a redirect response, but no check is performed on the path, which could be an absolute URL to an external domain. This Open redirect vulnerability can be exploited for example to mount effective phishing attacks.

Severity
6.1 (Medium)
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Show details on source website
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{
  "affected": [
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "symfony/symfony"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.7.0"
            },
            {
              "fixed": "2.7.38"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "symfony/symfony"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.8.0"
            },
            {
              "fixed": "2.8.31"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "symfony/symfony"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "3.2.0"
            },
            {
              "fixed": "3.2.14"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "symfony/symfony"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "3.3.0"
            },
            {
              "fixed": "3.3.13"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "symfony/security-http"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.7.0"
            },
            {
              "fixed": "2.7.38"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "symfony/security-http"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.8.0"
            },
            {
              "fixed": "2.8.31"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "symfony/security-http"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "3.2.0"
            },
            {
              "fixed": "3.2.14"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "symfony/security-http"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "3.3.0"
            },
            {
              "fixed": "3.3.13"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "symfony/security"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.7.0"
            },
            {
              "fixed": "2.7.38"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "symfony/security"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.8.0"
            },
            {
              "fixed": "2.8.31"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "symfony/security"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "3.2.0"
            },
            {
              "fixed": "3.2.14"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "symfony/security"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "3.3.0"
            },
            {
              "fixed": "3.3.13"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2017-16652"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-601"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2023-07-26T19:56:19Z",
    "nvd_published_at": "2018-06-13T16:29:00Z",
    "severity": "MODERATE"
  },
  "details": "An issue was discovered in Symfony 2.7.x before 2.7.38, 2.8.x before 2.8.31, 3.2.x before 3.2.14, and 3.3.x before 3.3.13. `DefaultAuthenticationSuccessHandler` or `DefaultAuthenticationFailureHandler` takes the content of the `_target_path` parameter and generates a redirect response, but no check is performed on the path, which could be an absolute URL to an external domain. This Open redirect vulnerability can be exploited for example to mount effective phishing attacks.",
  "id": "GHSA-r7p7-qr7p-2rrf",
  "modified": "2023-10-31T20:17:07Z",
  "published": "2022-05-14T01:21:36Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2017-16652"
    },
    {
      "type": "WEB",
      "url": "https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/security-http/CVE-2017-16652.yaml"
    },
    {
      "type": "WEB",
      "url": "https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/security/CVE-2017-16652.yaml"
    },
    {
      "type": "WEB",
      "url": "https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/symfony/CVE-2017-16652.yaml"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/symfony/symfony"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2019/03/msg00009.html"
    },
    {
      "type": "WEB",
      "url": "https://symfony.com/blog/cve-2017-16652-open-redirect-vulnerability-on-security-handlers"
    },
    {
      "type": "WEB",
      "url": "https://symfony.com/cve-2017-16652"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Symfony Open Redirect"
}

GHSA-R82C-J4MQ-5XFW

Vulnerability from github – Published: 2020-10-27 19:19 – Updated: 2020-10-27 19:19
VLAI
Summary
Update bitlyshortener to >=0.5.0 to prevent generating some invalid short URLs
Details

Impact

Due to a sudden upstream breaking change by Bitly, versions of bitlyshortener <0.5.0 can generate an invalid short URL when a vanity domain exists.

Patches

Upgrading bitlyshortener to 0.5.0 or newer will prevent the generation of any such invalid short URLs.

References

Show details on source website
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "bitlyshortener"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.5.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [],
  "database_specific": {
    "cwe_ids": [
      "CWE-601"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2020-10-27T19:19:44Z",
    "nvd_published_at": null,
    "severity": "HIGH"
  },
  "details": "### Impact\nDue to a sudden upstream breaking change by Bitly, versions of `bitlyshortener` \u003c0.5.0 can generate an invalid short URL when a vanity domain exists.\n\n### Patches\nUpgrading `bitlyshortener` to 0.5.0 or newer will prevent the generation of any such invalid short URLs.\n\n### References\n* [Release notes](https://github.com/impredicative/bitlyshortener/releases)",
  "id": "GHSA-r82c-j4mq-5xfw",
  "modified": "2020-10-27T19:19:44Z",
  "published": "2020-10-27T19:19:56Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/impredicative/bitlyshortener/security/advisories/GHSA-r82c-j4mq-5xfw"
    },
    {
      "type": "WEB",
      "url": "https://github.com/impredicative/bitlyshortener/commit/3d412feb77f3daf6f71536463734c2119a55968d"
    },
    {
      "type": "WEB",
      "url": "https://github.com/impredicative/bitlyshortener/releases/tag/0.5.0"
    },
    {
      "type": "WEB",
      "url": "https://pypi.org/project/bitlyshortener"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [],
  "summary": "Update bitlyshortener to \u003e=0.5.0 to prevent generating some invalid short URLs"
}

GHSA-R86G-243J-MQP7

Vulnerability from github – Published: 2025-01-27 21:30 – Updated: 2025-01-28 21:31
VLAI
Details

An issue in Xiamen Meitu Technology Co., Ltd. BeautyCam iOS v12.3.60 allows attackers to access sensitive user information via supplying a crafted link.

Severity
6.5 (Medium)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
Show details on source website
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{
  "affected": [],
  "aliases": [
    "CVE-2024-56947"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-601"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-01-27T19:15:16Z",
    "severity": "MODERATE"
  },
  "details": "An issue in Xiamen Meitu Technology Co., Ltd. BeautyCam iOS v12.3.60 allows attackers to access sensitive user information via supplying a crafted link.",
  "id": "GHSA-r86g-243j-mqp7",
  "modified": "2025-01-28T21:31:01Z",
  "published": "2025-01-27T21:30:53Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-56947"
    },
    {
      "type": "WEB",
      "url": "https://github.com/ZhouZiyi1/Vuls/blob/main/241208-BeautyCam/241208-BeautyCam.pdf"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-R88J-2W5R-2C6X

Vulnerability from github – Published: 2022-05-17 02:56 – Updated: 2025-04-20 03:33
VLAI
Details

cgiemail and cgiecho allow remote attackers to inject HTTP headers via a newline character in the redirect location.

Severity
6.1 (Medium)
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Show details on source website
To clipboard 

{
  "affected": [],
  "aliases": [
    "CVE-2017-5615"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-601"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2017-03-03T15:59:00Z",
    "severity": "MODERATE"
  },
  "details": "cgiemail and cgiecho allow remote attackers to inject HTTP headers via a newline character in the redirect location.",
  "id": "GHSA-r88j-2w5r-2c6x",
  "modified": "2025-04-20T03:33:35Z",
  "published": "2022-05-17T02:56:23Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2017-5615"
    },
    {
      "type": "WEB",
      "url": "https://news.cpanel.com/tsr-2017-0001-full-disclosure"
    },
    {
      "type": "WEB",
      "url": "http://www.openwall.com/lists/oss-security/2017/01/28/8"
    },
    {
      "type": "WEB",
      "url": "http://www.securityfocus.com/bid/95870"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-R8FJ-RFF6-F7H5

Vulnerability from github – Published: 2026-05-27 15:33 – Updated: 2026-07-01 19:43
VLAI
Summary
Jenkins Bitbucket OAuth Plugin does not restrict the redirect URL after login
Details

Jenkins Bitbucket OAuth Plugin 0.17 and earlier does not restrict the redirect URL after login.

This allows attackers to perform phishing attacks by having users go to a Jenkins URL that will forward them to a different site after successful authentication.

Bitbucket OAuth Plugin 0.18 only redirects to relative (Jenkins) URLs.

Severity
4.3 (Medium)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
Show details on source website
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{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 0.17"
      },
      "package": {
        "ecosystem": "Maven",
        "name": "org.jenkins-ci.plugins:bitbucket-oauth"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.18"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-48924"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-601"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-07-01T19:43:52Z",
    "nvd_published_at": "2026-05-27T15:16:32Z",
    "severity": "MODERATE"
  },
  "details": "Jenkins Bitbucket OAuth Plugin 0.17 and earlier does not restrict the redirect URL after login.\n\nThis allows attackers to perform phishing attacks by having users go to a Jenkins URL that will forward them to a different site after successful authentication.\n\nBitbucket OAuth Plugin 0.18 only redirects to relative (Jenkins) URLs.",
  "id": "GHSA-r8fj-rff6-f7h5",
  "modified": "2026-07-01T19:43:52Z",
  "published": "2026-05-27T15:33:27Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-48924"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/jenkinsci/bitbucket-oauth-plugin"
    },
    {
      "type": "WEB",
      "url": "https://www.jenkins.io/security/advisory/2026-05-27/#SECURITY-3761"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Jenkins Bitbucket OAuth Plugin does not restrict the redirect URL after login"
}

GHSA-R8HW-2VG3-PCPX

Vulnerability from github – Published: 2022-05-24 17:10 – Updated: 2022-05-24 17:10
VLAI
Details

There is an improper restriction of rendered UI layers or frames vulnerability in Micro Focus Service Manager Release Control versions 9.50 and 9.60. The vulnerability may result in the ability of malicious users to perform UI redress attacks.

Show details on source website
To clipboard 

{
  "affected": [],
  "aliases": [
    "CVE-2020-9517"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-601"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2020-03-09T16:15:00Z",
    "severity": "MODERATE"
  },
  "details": "There is an improper restriction of rendered UI layers or frames vulnerability in Micro Focus Service Manager Release Control versions 9.50 and 9.60. The vulnerability may result in the ability of malicious users to perform UI redress attacks.",
  "id": "GHSA-r8hw-2vg3-pcpx",
  "modified": "2022-05-24T17:10:31Z",
  "published": "2022-05-24T17:10:31Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2020-9517"
    },
    {
      "type": "WEB",
      "url": "https://softwaresupport.softwaregrp.com/doc/KM03604692"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

GHSA-R8XC-FMJG-37C5

Vulnerability from github – Published: 2026-08-06 18:30 – Updated: 2026-08-19 12:32
VLAI
Details

URL Redirection to Untrusted Site ('Open Redirect') vulnerability in the HTML5 scrubber in rrrene html_sanitize_ex allows an unauthenticated remote attacker to retarget a form already on the rendering page and receive whatever the victim submits, including credentials, via the form and formaction attributes on an element in sanitized HTML. HTML's form attribute associates an input with any form on the page by its id even when the input sits outside that form, and formaction on a submit control overrides the owning form's action. Neither attribute receives a scheme check, so an absolute cross-origin URL survives sanitizing.

No script executes. The scrubber allows neither form nor button, so the attacker cannot introduce a form of their own and the rendering page must already contain a form carrying an id.

This issue affects html_sanitize_ex: from 0.3.1 before 1.5.3.

Severity
6.1 (Medium)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
4.8 (Medium)
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:N/SC:H/SI:L/SA:N
Show details on source website
To clipboard 

{
  "affected": [],
  "aliases": [
    "CVE-2026-66370"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-601"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-06T16:16:48Z",
    "severity": "MODERATE"
  },
  "details": "URL Redirection to Untrusted Site (\u0027Open Redirect\u0027) vulnerability in the HTML5 scrubber in rrrene html_sanitize_ex allows an unauthenticated remote attacker to retarget a form already on the rendering page and receive whatever the victim submits, including credentials, via the form and formaction attributes on an \u003cinput\u003e element in sanitized HTML. HTML\u0027s form attribute associates an input with any form on the page by its id even when the input sits outside that form, and formaction on a submit control overrides the owning form\u0027s action. Neither attribute receives a scheme check, so an absolute cross-origin URL survives sanitizing.\n\nNo script executes. The scrubber allows neither form nor button, so the attacker cannot introduce a form of their own and the rendering page must already contain a form carrying an id.\n\nThis issue affects html_sanitize_ex: from 0.3.1 before 1.5.3.",
  "id": "GHSA-r8xc-fmjg-37c5",
  "modified": "2026-08-19T12:32:21Z",
  "published": "2026-08-06T18:30:49Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/rrrene/html_sanitize_ex/security/advisories/GHSA-w3f9-jjhw-wwvq"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-66370"
    },
    {
      "type": "WEB",
      "url": "https://github.com/rrrene/html_sanitize_ex/commit/21394e758cb0ffe12fb9953c30fdedc6016c8f9e"
    },
    {
      "type": "WEB",
      "url": "https://github.com/rrrene/html_sanitize_ex/commit/a1e804ed997e780ea71d14393cf2f701330553a6"
    },
    {
      "type": "WEB",
      "url": "https://cna.erlef.org/cves/CVE-2026-66370.html"
    },
    {
      "type": "WEB",
      "url": "https://osv.dev/vulnerability/EEF-CVE-2026-66370"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:N/SC:H/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
      "type": "CVSS_V4"
    }
  ]
}

GHSA-R95X-QFJJ-FJJ2

Vulnerability from github – Published: 2026-05-13 01:36 – Updated: 2026-06-08 23:53
VLAI
Summary
Authlib OIDC Implicit/Hybrid Authorization Vulnerable to Open Redirect
Details

Summary

An unauthenticated open redirect in Authlib's OpenIDImplicitGrant and OpenIDHybridGrant authorization endpoint lets a remote attacker cause the authorization server to issue an HTTP 302 to an attacker-chosen URL by submitting an authorization request that omits the openid scope.

Details

Vulnerable code

OpenIDImplicitGrant.validate_authorization_request in authlib/oidc/core/grants/implicit.py:

def validate_authorization_request(self):
    if not is_openid_scope(self.request.payload.scope):
        raise InvalidScopeError(
            "Missing 'openid' scope",
            redirect_uri=self.request.payload.redirect_uri,  # ← raw, unvalidated
            redirect_fragment=True,
        )
    redirect_uri = super().validate_authorization_request()
    ...

OpenIDHybridGrant.validate_authorization_request in authlib/oidc/core/grants/hybrid.py shares the same pattern.

Root cause

Both methods perform the openid scope presence check before delegating to super().validate_authorization_request(), which is where AuthorizationEndpointMixin.validate_authorization_redirect_uri validates the requested redirect_uri against the client's check_redirect_uri(...). The InvalidScopeError thrown by the scope check therefore carries attacker-controlled self.request.payload.redirect_uri.

OAuth2Error.__call__ in authlib/oauth2/base.py renders any error with a non-empty redirect_uri as an HTTP 302:

def __call__(self, uri=None):
    if self.redirect_uri:
        params = self.get_body()
        loc = add_params_to_uri(self.redirect_uri, params, self.redirect_fragment)
        return 302, "", [("Location", loc)]
    return super().__call__(uri=uri)

A malformed authorization request that selects OpenIDImplicitGrant or OpenIDHybridGrant and omits the openid scope is therefore redirected to a fully attacker-chosen URL.

This is a variant of the issue fixed in commit 3be08468 ("fix: redirecting to unvalidated redirect_uri on UnsupportedResponseTypeError") that was missed in the OIDC Implicit and Hybrid grants.

Preconditions

  1. The server registers OpenIDImplicitGrant or OpenIDHybridGrant (standard OIDC Implicit or Hybrid flow support).
  2. The attacker's request uses a response_type that matches either grant: id_token, id_token token, code id_token, code token, or code id_token token.
  3. scope does not contain openid.
  4. Any redirect_uri value.

No user authentication, no consent, no valid session, no CSRF token, and — notably — no valid client_id are required. The scope check runs before any client lookup, so any client_id value (including nonexistent ones) reaches the vulnerable code path.

PoC

The following unauthenticated GET is sufficient to induce the authorization server to redirect a victim's browser to an attacker-controlled URL:

GET /oauth/authorize
    ?response_type=id_token
    &client_id=anything
    &scope=profile
    &redirect_uri=https%3A%2F%2Fevil.example.com%2Fphish
    &state=s&nonce=n  HTTP/1.1
Host: victim-op.example

Server response:

HTTP/1.1 302 Found
Location: https://evil.example.com/phish#error=invalid_scope&error_description=Missing+%27openid%27+scope&state=s

Impact

  • Open redirect from a trusted authorization server origin. Victims receiving a phishing link see the legitimate OIDC provider's domain in the URL bar at the moment they click. The authorization server itself issues the 302 to the attacker's page, lending the attacker's landing page the OP's reputation and potentially satisfying domain-allow-list controls that trust the OP.
  • Phishing / credential harvesting leverage. The attacker's page can mimic the legitimate OP's consent screen or a relying-party error page to solicit credentials, MFA codes, or to continue a downstream confused-deputy attack.
  • RFC violation. RFC 6749 §4.1.2.1 and RFC 9700 (OAuth 2.0 Security BCP) §4.11 both state that an authorization server MUST NOT perform redirection to a redirect_uri that has not been validated against the client's registered URIs, even in error responses. The state parameter is echoed back, giving the attacker site a stable correlator.
  • No direct token/code leak. This flaw fires before any authorization decision, so no authorization codes, ID tokens, or access tokens are disclosed. The impact is limited to open-redirect phishing leverage. Combined with other issues (e.g., downstream SSO trust chains) it may contribute to account-takeover chains; on its own it is a Medium-severity open redirect.

Affected deployments

Any application using Authlib as an OIDC provider that registers OpenIDImplicitGrant and/or OpenIDHybridGrant — i.e. anyone supporting the Implicit flow or the Hybrid flow (response_type=code id_token, etc.) — is affected. Clients of an Authlib-based OP are not directly affected; this is a server-side issue.

Authorization servers that only register the plain AuthorizationCodeGrant (code flow, with or without PKCE and the OpenIDCode extension) are not affected by this specific variant: the code-flow grant validates redirect_uri before raising scope errors. If you were affected by the sibling issue fixed in 3be08468 (UnsupportedResponseTypeError), you should already be on 1.6.10 or later; this advisory is independent of that fix.

Suggested fix

The attached fix-oidc-open-redirect.patch reorders each method to delegate to its super (or call validate_code_authorization_request for Hybrid) first, and then performs the openid-scope check with the validated redirect_uri variable.

# authlib/oidc/core/grants/implicit.py
def validate_authorization_request(self):
    redirect_uri = super().validate_authorization_request()   # runs client + redirect_uri validation
    if not is_openid_scope(self.request.payload.scope):
        raise InvalidScopeError(
            "Missing 'openid' scope",
            redirect_uri=redirect_uri,                         # validated
            redirect_fragment=True,
        )
    try:
        validate_nonce(self.request, self.exists_nonce, required=True)
    except OAuth2Error as error:
        error.redirect_uri = redirect_uri
        error.redirect_fragment = True
        raise error
    return redirect_uri

An equivalent transform is applied to OpenIDHybridGrant.validate_authorization_request, invoking validate_code_authorization_request first and only then checking is_openid_scope.

Alternatively, inline a client = query_client(request.payload.client_id) + client.check_redirect_uri(request.payload.redirect_uri) guard before populating redirect_uri on the error — the pattern used in 3be08468.

The patch also adds regression tests analogous to test_unsupported_response_type_does_not_redirect from commit 3be08468, asserting rv.status_code == 400 and rv.headers.get("Location") is None for an unregistered redirect_uri with a non-openid scope.

Workarounds

No clean server-side workaround exists short of patching. Partial mitigations:

  • Unregister OpenIDImplicitGrant and OpenIDHybridGrant if the Implicit and Hybrid flows are not required. (RFC 9700 deprecates the Implicit flow and discourages Hybrid flows, so this is recommended anyway.)
  • Front the /authorize endpoint with a reverse proxy rule that rejects requests containing both a redirect_uri parameter and a scope that does not include openid when response_type matches the vulnerable set. This is fragile and not recommended as a primary control.

References

  • RFC 6749, §4.1.2.1 — Error Response (OAuth 2.0 authorization endpoint)
  • RFC 9700, §4.11 — Redirect URI validation
  • OpenID Connect Core 1.0, §3.2.2.6 / §3.3.2.6 — Authentication Error Response
  • Authlib commit 3be08468 — prior fix for the same class of issue in UnsupportedResponseTypeError (Authlib 1.6.10)
  • Authlib source (by symbol; verified in commit 5d2e603e):
  • OpenIDImplicitGrant.validate_authorization_request — authlib/oidc/core/grants/implicit.py
  • OpenIDHybridGrant.validate_authorization_request — authlib/oidc/core/grants/hybrid.py
  • OAuth2Error.__call__ — authlib/oauth2/base.py (renders errors with redirect_uri as HTTP 302)
  • AuthorizationEndpointMixin.validate_authorization_redirect_uri — authlib/oauth2/rfc6749/grants/base.py (the validation that is bypassed)
Severity
6.1 (Medium)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Show details on source website
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "authlib"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "1.7.0"
            },
            {
              "fixed": "1.7.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.7.0"
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 1.6.11"
      },
      "package": {
        "ecosystem": "PyPI",
        "name": "authlib"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.6.12"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-44681"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-601",
      "CWE-863"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-05-13T01:36:03Z",
    "nvd_published_at": "2026-05-27T20:16:37Z",
    "severity": "MODERATE"
  },
  "details": "### Summary\n\nAn unauthenticated open redirect in Authlib\u0027s `OpenIDImplicitGrant` and `OpenIDHybridGrant` authorization endpoint lets a remote attacker cause the authorization server to issue an HTTP 302 to an attacker-chosen URL by submitting an authorization request that omits the `openid` scope.\n\n### Details\n\n#### Vulnerable code\n\n`OpenIDImplicitGrant.validate_authorization_request` in `authlib/oidc/core/grants/implicit.py`:\n\n```python\ndef validate_authorization_request(self):\n    if not is_openid_scope(self.request.payload.scope):\n        raise InvalidScopeError(\n            \"Missing \u0027openid\u0027 scope\",\n            redirect_uri=self.request.payload.redirect_uri,  # \u2190 raw, unvalidated\n            redirect_fragment=True,\n        )\n    redirect_uri = super().validate_authorization_request()\n    ...\n```\n\n`OpenIDHybridGrant.validate_authorization_request` in `authlib/oidc/core/grants/hybrid.py` shares the same pattern.\n\n#### Root cause\n\nBoth methods perform the `openid` scope presence check before delegating to `super().validate_authorization_request()`, which is where `AuthorizationEndpointMixin.validate_authorization_redirect_uri` validates the requested `redirect_uri` against the client\u0027s `check_redirect_uri(...)`. The `InvalidScopeError` thrown by the scope check therefore carries attacker-controlled `self.request.payload.redirect_uri`.\n\n`OAuth2Error.__call__` in `authlib/oauth2/base.py` renders any error with a non-empty `redirect_uri` as an HTTP 302:\n\n```python\ndef __call__(self, uri=None):\n    if self.redirect_uri:\n        params = self.get_body()\n        loc = add_params_to_uri(self.redirect_uri, params, self.redirect_fragment)\n        return 302, \"\", [(\"Location\", loc)]\n    return super().__call__(uri=uri)\n```\n\nA malformed authorization request that selects `OpenIDImplicitGrant` or `OpenIDHybridGrant` and omits the `openid` scope is therefore redirected to a fully attacker-chosen URL.\n\nThis is a variant of the issue fixed in commit [`3be08468`](https://github.com/authlib/authlib/commit/3be08468) (\"fix: redirecting to unvalidated `redirect_uri` on `UnsupportedResponseTypeError`\") that was missed in the OIDC Implicit and Hybrid grants.\n\n#### Preconditions\n\n1. The server registers `OpenIDImplicitGrant` or `OpenIDHybridGrant` (standard OIDC Implicit or Hybrid flow support).\n2. The attacker\u0027s request uses a `response_type` that matches either grant: `id_token`, `id_token token`, `code id_token`, `code token`, or `code id_token token`.\n3. `scope` does not contain `openid`.\n4. Any `redirect_uri` value.\n\nNo user authentication, no consent, no valid session, no CSRF token, and \u2014 notably \u2014 no valid `client_id` are required. The scope check runs before any client lookup, so any `client_id` value (including nonexistent ones) reaches the vulnerable code path.\n\n### PoC\n\nThe following unauthenticated GET is sufficient to induce the authorization server to redirect a victim\u0027s browser to an attacker-controlled URL:\n\n```\nGET /oauth/authorize\n    ?response_type=id_token\n    \u0026client_id=anything\n    \u0026scope=profile\n    \u0026redirect_uri=https%3A%2F%2Fevil.example.com%2Fphish\n    \u0026state=s\u0026nonce=n  HTTP/1.1\nHost: victim-op.example\n```\n\nServer response:\n\n```\nHTTP/1.1 302 Found\nLocation: https://evil.example.com/phish#error=invalid_scope\u0026error_description=Missing+%27openid%27+scope\u0026state=s\n```\n\n### Impact\n\n- Open redirect from a trusted authorization server origin. Victims receiving a phishing link see the legitimate OIDC provider\u0027s domain in the URL bar at the moment they click. The authorization server itself issues the 302 to the attacker\u0027s page, lending the attacker\u0027s landing page the OP\u0027s reputation and potentially satisfying domain-allow-list controls that trust the OP.\n- Phishing / credential harvesting leverage. The attacker\u0027s page can mimic the legitimate OP\u0027s consent screen or a relying-party error page to solicit credentials, MFA codes, or to continue a downstream confused-deputy attack.\n- RFC violation. RFC 6749 \u00a74.1.2.1 and RFC 9700 (OAuth 2.0 Security BCP) \u00a74.11 both state that an authorization server MUST NOT perform redirection to a `redirect_uri` that has not been validated against the client\u0027s registered URIs, even in error responses. The `state` parameter is echoed back, giving the attacker site a stable correlator.\n- No direct token/code leak. This flaw fires before any authorization decision, so no authorization codes, ID tokens, or access tokens are disclosed. The impact is limited to open-redirect phishing leverage. Combined with other issues (e.g., downstream SSO trust chains) it may contribute to account-takeover chains; on its own it is a Medium-severity open redirect.\n\n#### Affected deployments\n\nAny application using Authlib as an OIDC provider that registers `OpenIDImplicitGrant` and/or `OpenIDHybridGrant` \u2014 i.e. anyone supporting the Implicit flow or the Hybrid flow (`response_type=code id_token`, etc.) \u2014 is affected. Clients of an Authlib-based OP are not directly affected; this is a server-side issue.\n\nAuthorization servers that only register the plain `AuthorizationCodeGrant` (code flow, with or without PKCE and the `OpenIDCode` extension) are not affected by this specific variant: the code-flow grant validates `redirect_uri` before raising scope errors. If you were affected by the sibling issue fixed in `3be08468` (`UnsupportedResponseTypeError`), you should already be on `1.6.10` or later; this advisory is independent of that fix.\n\n### Suggested fix\n\nThe attached `fix-oidc-open-redirect.patch` reorders each method to delegate to its super (or call `validate_code_authorization_request` for Hybrid) first, and then performs the `openid`-scope check with the validated `redirect_uri` variable.\n\n```python\n# authlib/oidc/core/grants/implicit.py\ndef validate_authorization_request(self):\n    redirect_uri = super().validate_authorization_request()   # runs client + redirect_uri validation\n    if not is_openid_scope(self.request.payload.scope):\n        raise InvalidScopeError(\n            \"Missing \u0027openid\u0027 scope\",\n            redirect_uri=redirect_uri,                         # validated\n            redirect_fragment=True,\n        )\n    try:\n        validate_nonce(self.request, self.exists_nonce, required=True)\n    except OAuth2Error as error:\n        error.redirect_uri = redirect_uri\n        error.redirect_fragment = True\n        raise error\n    return redirect_uri\n```\n\nAn equivalent transform is applied to `OpenIDHybridGrant.validate_authorization_request`, invoking `validate_code_authorization_request` first and only then checking `is_openid_scope`.\n\nAlternatively, inline a `client = query_client(request.payload.client_id)` + `client.check_redirect_uri(request.payload.redirect_uri)` guard before populating `redirect_uri` on the error \u2014 the pattern used in `3be08468`.\n\nThe patch also adds regression tests analogous to `test_unsupported_response_type_does_not_redirect` from commit `3be08468`, asserting `rv.status_code == 400` and `rv.headers.get(\"Location\") is None` for an unregistered `redirect_uri` with a non-`openid` scope.\n\n### Workarounds\n\nNo clean server-side workaround exists short of patching. Partial mitigations:\n\n- Unregister `OpenIDImplicitGrant` and `OpenIDHybridGrant` if the Implicit and Hybrid flows are not required. (RFC 9700 deprecates the Implicit flow and discourages Hybrid flows, so this is recommended anyway.)\n- Front the `/authorize` endpoint with a reverse proxy rule that rejects requests containing both a `redirect_uri` parameter and a `scope` that does not include `openid` when `response_type` matches the vulnerable set. This is fragile and not recommended as a primary control.\n\n### References\n\n- RFC 6749, \u00a74.1.2.1 \u2014 Error Response (OAuth 2.0 authorization endpoint)\n- RFC 9700, \u00a74.11 \u2014 Redirect URI validation\n- OpenID Connect Core 1.0, \u00a73.2.2.6 / \u00a73.3.2.6 \u2014 Authentication Error Response\n- Authlib commit [`3be08468`](https://github.com/authlib/authlib/commit/3be08468) \u2014 prior fix for the same class of issue in `UnsupportedResponseTypeError` (Authlib 1.6.10)\n- Authlib source (by symbol; verified in commit `5d2e603e`):\n  - `OpenIDImplicitGrant.validate_authorization_request` \u2014 `authlib/oidc/core/grants/implicit.py`\n  - `OpenIDHybridGrant.validate_authorization_request` \u2014 `authlib/oidc/core/grants/hybrid.py`\n  - `OAuth2Error.__call__` \u2014 `authlib/oauth2/base.py` (renders errors with `redirect_uri` as HTTP 302)\n  - `AuthorizationEndpointMixin.validate_authorization_redirect_uri` \u2014 `authlib/oauth2/rfc6749/grants/base.py` (the validation that is bypassed)",
  "id": "GHSA-r95x-qfjj-fjj2",
  "modified": "2026-06-08T23:53:47Z",
  "published": "2026-05-13T01:36:03Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/authlib/authlib/security/advisories/GHSA-r95x-qfjj-fjj2"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-44681"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/authlib/authlib"
    },
    {
      "type": "WEB",
      "url": "https://github.com/authlib/authlib/releases/tag/v1.6.12"
    },
    {
      "type": "WEB",
      "url": "https://github.com/authlib/authlib/releases/tag/v1.7.1"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pypa/advisory-database/tree/main/vulns/authlib/PYSEC-2026-188.yaml"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Authlib OIDC Implicit/Hybrid Authorization Vulnerable to Open Redirect"
}

GHSA-R992-XPH6-H7X2

Vulnerability from github – Published: 2022-02-12 00:00 – Updated: 2022-02-23 21:57
VLAI
Summary
Open redirect in microweber
Details

microweber prior to 1.2.11 is vulnerable to open redirect.

Severity
6.1 (Medium)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Show details on source website
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "microweber/microweber"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.2.11"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2022-0560"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-601"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2022-02-14T22:49:46Z",
    "nvd_published_at": "2022-02-11T13:15:00Z",
    "severity": "MODERATE"
  },
  "details": "microweber prior to 1.2.11 is vulnerable to open redirect.",
  "id": "GHSA-r992-xph6-h7x2",
  "modified": "2022-02-23T21:57:38Z",
  "published": "2022-02-12T00:00:48Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2022-0560"
    },
    {
      "type": "WEB",
      "url": "https://github.com/microweber/microweber/commit/72d4b12cc487f56a859a8570ada4efb77b4b8c63"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/microweber/microweber"
    },
    {
      "type": "WEB",
      "url": "https://huntr.dev/bounties/c9d586e7-0fa1-47ab-a2b3-b890e8dc9b25"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Open redirect in microweber"
}

GHSA-R9QJ-Q2G9-R74R

Vulnerability from github – Published: 2025-11-12 18:31 – Updated: 2025-11-12 18:31
VLAI
Details

In Splunk Enterprise versions below 10.0.1, 9.4.5, 9.3.7, 9.2.9, and Splunk Cloud Platform versions below 10.0.2503.5, 9.3.2411.111, and 9.3.2408.121, an unauthenticated attacker could craft a malicious URL using the return_to parameter of the Splunk Web login endpoint. When an authenticated user visits the malicious URL, it could cause an unvalidated redirect to an external malicious site. To be successful, the attacker has to trick the victim into initiating a request from their browser. The unauthenticated attacker should not be able to exploit the vulnerability at will.

Severity
3.1 (Low)
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N
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To clipboard 

{
  "affected": [],
  "aliases": [
    "CVE-2025-20378"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-601"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-11-12T18:15:34Z",
    "severity": "LOW"
  },
  "details": "In Splunk Enterprise versions below 10.0.1, 9.4.5, 9.3.7, 9.2.9, and Splunk Cloud Platform versions below 10.0.2503.5, 9.3.2411.111, and 9.3.2408.121, an unauthenticated attacker could craft a malicious URL using the `return_to` parameter of the Splunk Web login endpoint. When an authenticated user visits the malicious URL, it could cause an unvalidated redirect to an external malicious site. To be successful, the attacker has to trick the victim into initiating a request from their browser. The unauthenticated attacker should not be able to exploit the vulnerability at will.",
  "id": "GHSA-r9qj-q2g9-r74r",
  "modified": "2025-11-12T18:31:25Z",
  "published": "2025-11-12T18:31:25Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-20378"
    },
    {
      "type": "WEB",
      "url": "https://advisory.splunk.com/advisories/SVD-2025-1101"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N",
      "type": "CVSS_V3"
    }
  ]
}
Mitigation MIT-5
Implementation

Strategy: Input Validation

  • Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
  • When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue."
  • Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
  • Use a list of approved URLs or domains to be used for redirection.
Mitigation
Architecture and Design

Use an intermediate disclaimer page that provides the user with a clear warning that they are leaving the current site. Implement a long timeout before the redirect occurs, or force the user to click on the link. Be careful to avoid XSS problems (CWE-79) when generating the disclaimer page.

Mitigation MIT-21.2
Architecture and Design

Strategy: Enforcement by Conversion

  • When the set of acceptable objects, such as filenames or URLs, is limited or known, create a mapping from a set of fixed input values (such as numeric IDs) to the actual filenames or URLs, and reject all other inputs.
  • For example, ID 1 could map to "/login.asp" and ID 2 could map to "http://www.example.com/". Features such as the ESAPI AccessReferenceMap [REF-45] provide this capability.
Mitigation
Architecture and Design

Ensure that no externally-supplied requests are honored by requiring that all redirect requests include a unique nonce generated by the application [REF-483]. Be sure that the nonce is not predictable (CWE-330).

Mitigation MIT-6
Architecture and Design Implementation

Strategy: Attack Surface Reduction

  • Understand all the potential areas where untrusted inputs can enter your software: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any external systems that provide data to the application. Remember that such inputs may be obtained indirectly through API calls.
  • Many open redirect problems occur because the programmer assumed that certain inputs could not be modified, such as cookies and hidden form fields.
Mitigation MIT-29
Operation

Strategy: Firewall

Use an application firewall that can detect attacks against this weakness. It can be beneficial in cases in which the code cannot be fixed (because it is controlled by a third party), as an emergency prevention measure while more comprehensive software assurance measures are applied, or to provide defense in depth [REF-1481].

CAPEC-178: Cross-Site Flashing

An attacker is able to trick the victim into executing a Flash document that passes commands or calls to a Flash player browser plugin, allowing the attacker to exploit native Flash functionality in the client browser. This attack pattern occurs where an attacker can provide a crafted link to a Flash document (SWF file) which, when followed, will cause additional malicious instructions to be executed. The attacker does not need to serve or control the Flash document. The attack takes advantage of the fact that Flash files can reference external URLs. If variables that serve as URLs that the Flash application references can be controlled through parameters, then by creating a link that includes values for those parameters, an attacker can cause arbitrary content to be referenced and possibly executed by the targeted Flash application.

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