Vulnerability · Published Mar 9, 2026 · Assigned by GitHub_M

CVE-2026-30927Admidio: Event participation IDOR - non-leaders can register other users for events via user_uuid parameter

Medium 5.3

In plain English

A medium-severity authorization bypass via user-controlled key in admidio from Admidio. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 21% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)5.3Medium

Exploit odds (30 days)0.3%top 78.8% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

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.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Packagist	admidio/admidio	5.0.6	GHSA-7pfv-hr63-h7cw

Affected products (as reported)

Vendor	Product	Versions
Admidio	admidio	< 5.0.6

Weakness: CWE-639 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N

References

https://github.com/Admidio/admidio/security/advisories/GHSA-7pfv-hr63-h7cw x_refsource_CONFIRM
https://github.com/Admidio/admidio/issues/1985 x_refsource_MISC
https://github.com/Admidio/admidio/commit/e47f70cc3cbcdb39635fdbaaef02d19f604b8c3e x_refsource_MISC