CVE-2026-41671 — admidio/admidio
MEDIUMCVE-2026-41671 is a medium-severity (CVSS 6.8) Improper Authentication vulnerability in admidio/admidio. A fix is available for admidio/admidio — see the affected versions and patch details below.
Admidio: OIDC Token Introspection Endpoint Returns Active for All Tokens Without Validation
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-41671.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2026-41671 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,166 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
admidio/admidioReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | admidio/admidio | all versions | 5.0.9composer require admidio/admidio:^5.0.9 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for admidio/admidio, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update admidio/admidio to 5.0.9 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-41671 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-41671 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-41671. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-41671 in your dependencies?
O3 Security finds CVE-2026-41671 across Packagist dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.