Vulnerability-Lookup

ubuntu-cve-2026-49283

Vulnerability from osv_ubuntu

Published

2026-08-19 15:17

Modified

2026-09-02 16:18

Summary

Details

The SimpleSAMLphp SAML2 library is a PHP library for SAML2 related functionality. Prior to versions 4.19.3, 4.20.2, 5.0.6, and 6.2.1, the HTTPArtifact::receive() flow can treat an unsigned embedded SAML Response as cryptographically valid for the wrong identity provider. SOAPClient::addSSLValidator() attaches a TLS-based validator to the outer SOAP ArtifactResponse, while the embedded Response receives a validator that delegates to the outer message and is later checked against metadata selected from the embedded response issuer rather than necessarily the artifact issuer. SOAPClient::validateSSL() returns normally when the TLS public key does not match the key being validated, and SAML2\Message::validate() treats a validator call that does not throw as successful. In a multi-IdP federation, a malicious or lower-trust IdP can therefore provide an ArtifactResponse containing an unsigned Response that claims a higher-trust victim IdP as issuer and authenticate as arbitrary users with attacker-chosen assertion attributes, NameID, and session data. This issue is fixed in versions 4.19.3, 4.20.2, 5.0.6, and 6.2.1.

Severity

8.7 (High)


                    
                      CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2026-49283	REPORT
	https://www.cve.org/CVERecord?id=CVE-2026-49283	REPORT

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "simplesamlphp",
            "binary_version": "1.14.0-1ubuntu2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:16.04:LTS",
        "name": "simplesamlphp",
        "purl": "pkg:deb/ubuntu/simplesamlphp@1.14.0-1ubuntu2?arch=source\u0026distro=xenial"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.13.2-1",
        "1.14.0-1",
        "1.14.0-1ubuntu2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "simplesamlphp",
            "binary_version": "1.15.3-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:18.04:LTS",
        "name": "simplesamlphp",
        "purl": "pkg:deb/ubuntu/simplesamlphp@1.15.3-1?arch=source\u0026distro=bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.14.15-1",
        "1.15.0-1",
        "1.15.1-1",
        "1.15.2-1",
        "1.15.3-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "simplesamlphp",
            "binary_version": "1.18.4-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "simplesamlphp",
        "purl": "pkg:deb/ubuntu/simplesamlphp@1.18.4-1?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.17.5-1",
        "1.17.6-1",
        "1.17.6-2",
        "1.18.1-1",
        "1.18.4-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "simplesamlphp",
            "binary_version": "1.19.1-1.1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "simplesamlphp",
        "purl": "pkg:deb/ubuntu/simplesamlphp@1.19.1-1.1?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.19.1-1",
        "1.19.1-1.1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "simplesamlphp",
            "binary_version": "1.19.7-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "simplesamlphp",
        "purl": "pkg:deb/ubuntu/simplesamlphp@1.19.7-1?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.19.7-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "simplesamlphp",
            "binary_version": "1.19.7-2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "simplesamlphp",
        "purl": "pkg:deb/ubuntu/simplesamlphp@1.19.7-2?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.19.7-2"
      ]
    }
  ],
  "aliases": [],
  "details": "The SimpleSAMLphp SAML2 library is a PHP library for SAML2 related functionality. Prior to versions 4.19.3, 4.20.2, 5.0.6, and 6.2.1, the HTTPArtifact::receive() flow can treat an unsigned embedded SAML Response as cryptographically valid for the wrong identity provider. SOAPClient::addSSLValidator() attaches a TLS-based validator to the outer SOAP ArtifactResponse, while the embedded Response receives a validator that delegates to the outer message and is later checked against metadata selected from the embedded response issuer rather than necessarily the artifact issuer. SOAPClient::validateSSL() returns normally when the TLS public key does not match the key being validated, and SAML2\\Message::validate() treats a validator call that does not throw as successful. In a multi-IdP federation, a malicious or lower-trust IdP can therefore provide an ArtifactResponse containing an unsigned Response that claims a higher-trust victim IdP as issuer and authenticate as arbitrary users with attacker-chosen assertion attributes, NameID, and session data. This issue is fixed in versions 4.19.3, 4.20.2, 5.0.6, and 6.2.1.",
  "id": "UBUNTU-CVE-2026-49283",
  "modified": "2026-09-02T16:18:22Z",
  "published": "2026-08-19T15:17:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-49283"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-49283"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-49283"
  ]
}

CVE-2026-49283 (GCVE-0-2026-49283)

Vulnerability from cvelistv5 – Published: 2026-08-19 14:47 – Updated: 2026-08-19 18:19

Title

SimpleSAMLphp HTTP-Artifact TLS validator confusion allows cross-IdP authentication bypass

Summary

Severity

8.7 (High)


                        
                          CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-19 18:16 UTC

CWE

CWE-295 - Improper Certificate Validation

Assigner

GitHub_M mitre root

References

5 references

URL	Tags
https://github.com/simplesamlphp/saml2/security/a…	x_refsource_CONFIRM
https://github.com/simplesamlphp/saml2/commit/4a7…	x_refsource_MISC
https://github.com/simplesamlphp/saml2/commit/a2c…	x_refsource_MISC
https://github.com/simplesamlphp/saml2/commit/d5c…	x_refsource_MISC
https://github.com/simplesamlphp/saml2/commit/e2d…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
simplesamlphp	saml2	Affected: < 4.19.3 Affected: >= 4.20.0, < 4.20.2 Affected: >= 5.0.0, < 5.0.6 Affected: >= 6.0.0, < 6.2.1

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-49283",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-08-19T18:16:10.690773Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-08-19T18:19:10.978Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "saml2",
          "vendor": "simplesamlphp",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 4.19.3"
            },
            {
              "status": "affected",
              "version": "\u003e= 4.20.0, \u003c 4.20.2"
            },
            {
              "status": "affected",
              "version": "\u003e= 5.0.0, \u003c 5.0.6"
            },
            {
              "status": "affected",
              "version": "\u003e= 6.0.0, \u003c 6.2.1"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "The SimpleSAMLphp SAML2 library is a PHP library for SAML2 related functionality. Prior to versions 4.19.3, 4.20.2, 5.0.6, and 6.2.1, the HTTPArtifact::receive() flow can treat an unsigned embedded SAML Response as cryptographically valid for the wrong identity provider. SOAPClient::addSSLValidator() attaches a TLS-based validator to the outer SOAP ArtifactResponse, while the embedded Response receives a validator that delegates to the outer message and is later checked against metadata selected from the embedded response issuer rather than necessarily the artifact issuer. SOAPClient::validateSSL() returns normally when the TLS public key does not match the key being validated, and SAML2\\Message::validate() treats a validator call that does not throw as successful. In a multi-IdP federation, a malicious or lower-trust IdP can therefore provide an ArtifactResponse containing an unsigned Response that claims a higher-trust victim IdP as issuer and authenticate as arbitrary users with attacker-chosen assertion attributes, NameID, and session data. This issue is fixed in versions 4.19.3, 4.20.2, 5.0.6, and 6.2.1."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 8.7,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "HIGH",
            "scope": "CHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-295",
              "description": "CWE-295: Improper Certificate Validation",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-19T14:47:05.519Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/simplesamlphp/saml2/security/advisories/GHSA-6929-8p9f-26jx",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/simplesamlphp/saml2/security/advisories/GHSA-6929-8p9f-26jx"
        },
        {
          "name": "https://github.com/simplesamlphp/saml2/commit/4a71b20d8d845579fd0a54d6449c265b40db459d",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/simplesamlphp/saml2/commit/4a71b20d8d845579fd0a54d6449c265b40db459d"
        },
        {
          "name": "https://github.com/simplesamlphp/saml2/commit/a2c1ac588c70d7b7998546cf32675fb113f22a5f",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/simplesamlphp/saml2/commit/a2c1ac588c70d7b7998546cf32675fb113f22a5f"
        },
        {
          "name": "https://github.com/simplesamlphp/saml2/commit/d5c213132ef671c0018a11252322034dbddd735a",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/simplesamlphp/saml2/commit/d5c213132ef671c0018a11252322034dbddd735a"
        },
        {
          "name": "https://github.com/simplesamlphp/saml2/commit/e2df7992609964951b2a3e7d6566b7427b2a968f",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/simplesamlphp/saml2/commit/e2df7992609964951b2a3e7d6566b7427b2a968f"
        }
      ],
      "source": {
        "advisory": "GHSA-6929-8p9f-26jx",
        "discovery": "UNKNOWN"
      },
      "title": "SimpleSAMLphp HTTP-Artifact TLS validator confusion allows cross-IdP authentication bypass"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-49283",
    "datePublished": "2026-08-19T14:47:05.519Z",
    "dateReserved": "2026-05-28T20:07:58.861Z",
    "dateUpdated": "2026-08-19T18:19:10.978Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.