Admidio before 5.0.17 contains an improper access control vulnerability that allows authenticated members to register event guests by submitting the additional_guests field when guests are disallowed. Attackers can set additional_guests to the remaining seat count in modules/events/events_function.php to exhaust event capacity and block other members from registering.
Fix
Nothing published yet: no patch, vendor advisory or mitigation reference on NVD, no vendor advisory in the News for this CVE, not in CISA's KEV, no fixed package version. BaselineWatch does not guess at one.
Change history 3
- StatusPublished → DeferredNVD modified 2026-10-27 14:16
- CVSS5.3 (v4.0, CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N) → 5.3 (v4.0, CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X)NVD modified 2026-10-27 14:16
- First seenCVSS 5.3 · admidioNVD modified 2026-10-27 13:07
Affected (CPE criteria) 0
NVD has not attached CPE configurations yet.
References 7
- https://github.com/Admidio/admidio
- https://github.com/Admidio/admidio/blob/v5.0.16/modules/events/events_function.php#L446-L462
- https://github.com/Admidio/admidio/commit/5b0ee3585d2a69a6e85fee00b7b93f3ebc1e44d9
- https://github.com/Admidio/admidio/issues/2231
- https://github.com/Admidio/admidio/releases/tag/v5.0.17
- https://github.com/Admidio/admidio/security/advisories/GHSA-92g9-59rr-c3qg
- https://www.vulncheck.com/advisories/admidio-before-5.0.17-event-guest-restriction-bypass-via-events-function-php