Admidio: OIDC Token Introspection Endpoint Returns Active for All Tokens Without Validation

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

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

EPSS

• CVE-2026-41671: 0.32% estimated exploitation activity in the next 30 days; percentile 25.37 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary 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. Details The vulnerability is in src/SSO/Service/OIDCService.php, lines 604-619: The introspection endpoint is routed at modules/sso/index.php, line 58-59: The router comment at line 35 says "Login checks will be done in the individual endpoint handler functions!"…

Published by the source

29 Apr 2026, 21:58 UTC

Last modified by the source

8 May 2026, 20:14 UTC

Source last checked

26 Oct 2026, 14:40 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-9xx5-cv6j-x533

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: CVE-2026-41671

Advisory: Admidio: OIDC Token Introspection Endpoint Returns Active for All Tokens Without Validation
IDs: CVE-2026-41671, GHSA-9xx5-cv6j-x533
Record: https://patchnext.com/advisories/cve-2026-41671 (revision 1, source checked 26 Oct 2026, 14:40 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.8)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: admidio/admidio 5.0.9. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist admidio/admidio: affected <= 5.0.8; fixed in 5.0.9

## Suggested inspection (read-only)
- Packagist admidio/admidio: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on admidio/admidio.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-9xx5-cv6j-x533 (GitHub-reviewed advisory GHSA-9xx5-cv6j-x533 lists affected ranges: Packagist admidio/admidio >=0 <=5.0.8)

Commands are suggestions: review each one before running it.