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National Vulnerability Database

National Vulnerability Database

NVD

National Vulnerability Database
  1. Vulnerabilities

CVE-2026-57580 Detail

Description

authentik is an open-source identity provider. Prior to 2026.2.6 and 2026.5.5, an inbound SAML Source configured with the non-default USERNAME_LINK or EMAIL_LINK user-matching mode interprets an XML comment in a NameID differently from the identity provider's signed assertion. An attacker with an account on the source identity provider who can set the account's NameID can inject an XML comment that truncates the value used by authentik to the text before the comment while the signed assertion remains valid. A crafted NameID can therefore truncate to a victim's username or email and bind the attacker's external identity to the victim's existing account. This grants full takeover without the victim's password or the identity provider's private key, and the malicious link persists so later logins succeed without the comment. Sources using the default unique-identifier matching mode and authentik's outbound SAML Provider role are not affected. This issue is fixed in versions 2026.2.6 and 2026.5.5.


Metrics

 
NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.
CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

Nist CVSS score does not match with CNA score
CNA:  GitHub, Inc.
CVSS-B 9.4 CRITICAL
Vector:  CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N

References to Advisories, Solutions, and Tools

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URL Source(s) Tag(s)
https://github.com/goauthentik/authentik/commit/6bd00f09f1f6b5bc5212a10340418fa1b264f02c GitHub, Inc.
https://github.com/goauthentik/authentik/commit/8704a1b89d7bf46bcef0d3c434c821b937fdecc3 GitHub, Inc.
https://github.com/goauthentik/authentik/pull/24057 GitHub, Inc.
https://github.com/goauthentik/authentik/pull/24062 GitHub, Inc.
https://github.com/goauthentik/authentik/releases/tag/version/2026.2.6 GitHub, Inc.
https://github.com/goauthentik/authentik/releases/tag/version/2026.5.5 GitHub, Inc.
https://github.com/goauthentik/authentik/security/advisories/GHSA-35v6-hv2g-6992 GitHub, Inc.

Weakness Enumeration

CWE-ID CWE Name Source
CWE-436 Interpretation Conflict GitHub, Inc.  

Change History

2 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2026-57580
NVD Published Date:
08/18/2026
NVD Last Modified:
08/18/2026
Source:
GitHub, Inc.