# CVE-2026-41671: Admidio: OIDC Token Introspection Endpoint Returns Active for All Tokens Without Validation

> Admidio's OIDC introspection endpoint falsely validates all tokens, allowing attackers to bypass authentication and gain unauthorized access.

- **Severity:** Medium 6.8 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 7 May 2026
- **Updated:** 7 May 2026
- **Also known as:** GHSA-9xx5-cv6j-x533

## What is CVE-2026-41671?

CVE-2026-41671 is a medium-severity authentication bypass vulnerability in admidio, published on 7 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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.

Weakness: CWE-287 (Improper Authentication)

## Which versions are affected by CVE-2026-41671?

2 open source packages ship an affected version, including admidio/admidio.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `admidio/admidio` | Packagist | All versions | 5.0.9 |
| `admidio/admidio` | Packagist | All versions | 5.0.9 |

## How do I fix CVE-2026-41671?

Upgrade admidio/admidio to 5.0.9 or later.

## Is CVE-2026-41671 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-41671 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-41671 and fix it if it is affected.

What it is: CVE-2026-41671 is a medium-severity authentication bypass vulnerability in admidio, published on 7 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-41671 exists.

Affected packages and fixed versions:
- admidio/admidio (Packagist): affected all versions; fixed in 5.0.9
- admidio/admidio (Packagist): affected all versions; fixed in 5.0.9

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-41671/ (Markdown: https://insights.sbomify.com/CVE-2026-41671/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-41671
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-41671
- OSV: https://osv.dev/vulnerability/CVE-2026-41671

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-41671/
Summaries are generated and may contain mistakes; the official description above is the record.