Vulnerability-Lookup

CVE-2026-47201 (GCVE-0-2026-47201)

Vulnerability from cvelistv5 – Published: 2026-06-02 20:30 – Updated: 2026-06-03 14:08

Title

authentik: XML Signature Wrapping in SAML Source ACS allows authentication as arbitrary federated user

Summary

authentik is an open-source identity provider. Prior to versions 2025.12.5, 2026.2.3, and 2026.5.1, authentik's SAML Source ACS endpoint is vulnerable to XML Signature Wrapping when validating upstream SAML responses. An attacker with any account at the upstream IdP can reuse a valid signed assertion to authenticate as another federated user. This issue has been patched in versions 2025.12.5, 2026.2.3, and 2026.5.1.

Severity

8.5 (High)


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

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator (v2.0.3)

CWE

CWE-20 - Improper Input Validation

Assigner

GitHub_M

References

1 reference

URL	Tags
https://github.com/goauthentik/authentik/security…	x_refsource_CONFIRM

Impacted products

1 product

Vendor	Product	Version
goauthentik	authentik	Affected: < 2025.12.5 Affected: < 2026.2.3 Affected: < 2026.5.1

Show details on NVD website

JSON

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FKIE_CVE-2026-47201

Vulnerability from fkie_nvd - Published: 2026-06-02 21:16 - Updated: 2026-06-02 21:16

Severity

8.5 (High) - CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H

Summary

References

	URL	Tags
	security-advisories@github.com	https://github.com/goauthentik/authentik/security/advisories/GHSA-c3m2-jqmq-pvp3

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "authentik is an open-source identity provider. Prior to versions 2025.12.5, 2026.2.3, and 2026.5.1, authentik\u0027s SAML Source ACS endpoint is vulnerable to XML Signature Wrapping when validating upstream SAML responses. An attacker with any account at the upstream IdP can reuse a valid signed assertion to authenticate as another federated user. This issue has been patched in versions 2025.12.5, 2026.2.3, and 2026.5.1."
    }
  ],
  "id": "CVE-2026-47201",
  "lastModified": "2026-06-02T21:16:27.940",
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}

GHSA-C3M2-JQMQ-PVP3

Vulnerability from github – Published: 2026-05-29 20:25 – Updated: 2026-05-29 20:25

Summary

authentik's XML Signature Wrapping in SAML Source ACS allows authentication as arbitrary federated user

Details

Summary

authentik's SAML Source ACS endpoint is vulnerable to XML Signature Wrapping when validating upstream SAML responses. An attacker with any account at the upstream IdP can reuse a valid signed assertion to authenticate as another federated user.

### Patches

authentik 2026.5.1, 2026.2.4 and 2025.12.6 fix this issue.

### Impact

Affected: authentik deployments using a SAML Source for upstream SAML federation with signed assertions, or signed responses without signed assertions. Not affected: deployments that do not use SAML Source for upstream SAML federation.

The SAML Source trusts that the verified XML signature belongs to the assertion or response that authentik later consumes. A crafted SAML response can make signature verification succeed against the attacker's original signed assertion while authentik reads identity data from a different forged assertion.

An attacker first completes a legitimate login to the upstream IdP and captures the signed SAML response sent through their browser. They then submit a modified response to the ACS endpoint where the valid signature still verifies, but the consumed assertion contains a victim identifier or attacker-chosen attributes.

The attacker can authenticate as a victim who has previously used the SAML Source, or as a local user matched by forged email or username when those matching modes are enabled.

### Workarounds

Disable affected SAML Sources, or block access to their ACS endpoints.

### For more information

If there are any questions or comments about this advisory:

Send an email to security@goauthentik.io

Severity

8.5 (High)


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

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "goauthentik.io"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.0.0-20260528144335-a370d76d23c7"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-47201"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-287"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-05-29T20:25:48Z",
    "nvd_published_at": null,
    "severity": "HIGH"
  },
  "details": "### Summary\n \n authentik\u0027s SAML Source ACS endpoint is vulnerable to XML Signature Wrapping when validating upstream SAML responses. An attacker with any account at the upstream IdP can reuse a valid signed assertion to authenticate as another federated user.\n \n ### Patches\n \n authentik 2026.5.1, 2026.2.4 and 2025.12.6 fix this issue.\n \n ### Impact\n \n Affected: authentik deployments using a SAML Source for upstream SAML federation with signed assertions, or signed responses without signed assertions. Not affected: deployments that do not use SAML Source for upstream SAML federation.\n \n The SAML Source trusts that the verified XML signature belongs to the assertion or response that authentik later consumes. A crafted SAML response can make signature verification succeed against the attacker\u0027s original signed assertion while authentik reads identity data from a different forged assertion.\n \n An attacker first completes a legitimate login to the upstream IdP and captures the signed SAML response sent through their browser. They then submit a modified response to the ACS endpoint where the valid signature still verifies, but the consumed assertion contains a victim identifier or attacker-chosen attributes.\n \n The attacker can authenticate as a victim who has previously used the SAML Source, or as a local user matched by forged email or username when those matching modes are enabled.\n \n ### Workarounds\n \n Disable affected SAML Sources, or block access to their ACS endpoints.\n \n ### For more information\n \nIf there are any questions or comments about this advisory:\n \n - Send an email to [security@goauthentik.io](mailto:security@goauthentik.io)",
  "id": "GHSA-c3m2-jqmq-pvp3",
  "modified": "2026-05-29T20:25:48Z",
  "published": "2026-05-29T20:25:48Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/goauthentik/authentik/security/advisories/GHSA-c3m2-jqmq-pvp3"
    },
    {
      "type": "WEB",
      "url": "https://github.com/goauthentik/authentik/commit/a370d76d23c7de0fceed064ca322e33e6ebf0119"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/goauthentik/authentik"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "authentik\u0027s XML Signature Wrapping in SAML Source ACS allows authentication as arbitrary federated user"
}

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.

Action not permitted

CVE-2026-47201 (GCVE-0-2026-47201)

FKIE_CVE-2026-47201

GHSA-C3M2-JQMQ-PVP3

Summary

Tags

Sightings

Nomenclature