Auth bypass in Admidio
CVE-2026-30927
Admidio is an open-source user management solution. Prior to 5.0.6, in modules/events/events_function.php, the event participation logic allows any user who can participate in an event to register OTHER users by manipulating the user_uuid GET parameter. The condition uses || (OR), meaning if possibleToParticipate() returns true (event is open for participation), ANY user - not just leaders - can specify a different user_uuid and register/cancel participation for that user. The code then operates on $user->getValue('usr_id') (the target user from user_uuid) rather than the current user. This vulnerability is fixed in 5.0.6.
Vulnerability class: IDOR (Insecure Direct Object Reference)
EPSS: 0.003 (16.9th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L.
Affected products
- Admidio — versions < 5.0.6
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Mitigation, Vendor Advisory)
- security-advisories@github.com (x_refsource_MISC, Issue Tracking)
- security-advisories@github.com (Patch, x_refsource_MISC)
Frequently asked questions
- What is CVE-2026-30927?
- CVE-2026-30927 is a medium-severity vulnerability in Admidio, classified under Authorization Bypass Through User-Controlled Key. CVSS score: 5.4/10. Published 2026-03-10.
- How severe is CVE-2026-30927?
- Medium severity. CVSS v3 base score is 5.4 out of 10.