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Improper AuthenticationWeakness · CWE-287

CVE-2026-41671

MEDIUM · 6.8 CVSS v3.1 Published 2026-05-07
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
77/100
Remediation priority · High
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Admidio is an open-source user management solution. Prior to version 5.0.9, the OIDC token introspection endpoint (/modules/sso/index.php/oidc/introspect) always returns {"active": true} for every request, regardless of whether a valid token is provided, whether the token is expired, revoked, or completely fabricated. The endpoint performs no authentication of the calling resource server and no validation of the submitted token. Any resource server that relies on this introspection endpoint to validate access tokens will accept all requests as authorized, enabling complete authentication bypass. Additionally, the OIDC token revocation endpoint (/oidc/revoke) returns {"revoked": true} without actually revoking any token, preventing resource servers from invalidating compromised credentials. This issue has been patched in version 5.0.9.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

The OIDC token introspection endpoint in Admidio versions before 5.0.9 unconditionally returns {"active":true} without validating the submitted token or authenticating the calling resource server. This allows any caller to bypass authentication entirely by simply querying the introspection endpoint. Additionally, the revocation endpoint claims success without actually invalidating tokens.

MitigationUpgrade to Admidio version 5.0.9 or later to receive the patch. Review OIDC/OAuth2 integrations to confirm they are not relying on the vulnerable endpoints.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
High
Privileges
None
User interaction
None
Scope
Changed
Confidentiality
None
Integrity
High
Availability
None

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify Admidio installation
    Locate the Admidio installation directory and check for version information in configuration files, changelog, or the admidio version constant
    Affected if Admidio is installed and version is below 5.0.9
  2. Verify OIDC/OAuth2 is configured
    Review the Admidio configuration files for OIDC or OAuth2 provider settings, typically found in the admidio config or plugin configuration directories
    Affected if OIDC or OAuth2 integration is enabled with a configured provider
  3. Test introspection endpoint accessibility
    Send an unauthenticated HTTP request to the token introspection endpoint (typically /oauth2/token_introspect or similar path under the OIDC plugin) with a dummy or expired token
    Affected if The endpoint returns {"active":true} without rejecting the request or requiring authentication
  4. Test revocation endpoint behavior
    Send a token revocation request to the revocation endpoint (typically /oauth2/revoke or similar path under the OIDC plugin) and verify whether the token actually becomes invalid
    Affected if The endpoint returns a success response but the token remains usable at the resource server

A user is affected if running Admidio version below 5.0.9 with OIDC/OAuth2 enabled, where the introspection endpoint accepts unauthenticated requests or the revocation endpoint does not actually invalidate tokens.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade to Admidio version 5.0.9 or later to receive the patch. Review OIDC/OAuth2 integrations to confirm they are not relying on the vulnerable endpoints.

Recommended fix High confidence

Admidio version 5.0.9

  1. 1. Identify the current Admidio installation version (check admidio/version.php or similar)
  2. 2. Backup the database and all Admidio files before upgrading
  3. 3. Download Admidio version 5.0.9 or later from the official repository (github.com/admidio/admidio)
  4. 4. Replace the existing Admidio files with the new version, preserving configuration and custom files
  5. 5. Run any database migration scripts included in the upgrade
  6. 6. Verify the OIDC token introspection endpoint now properly validates tokens (should return {"active": false} for invalid/expired tokens)
  7. 7. Verify the OIDC token revocation endpoint actually revokes tokens

Generated from the published advisory — verify against the referenced sources before acting.

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation1.0 h
  • Testing3.0 h
  • Review / QA2.0 h
8.0 hours of engineering $1,390
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-41671 in production — separate from our analysis above.

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