Description
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.
References8
- github.com/Admidio/admidio
- github.com/Admidio/admidio/blob/v5.0.16/modules/events/events_f…
- github.com/Admidio/admidio/commit/5b0ee3585d2a69a6e85fee00b7b93…
- github.com/Admidio/admidio/issues/2231
- github.com/Admidio/admidio/releases/tag/v5.0.17
- github.com/Admidio/admidio/security/advisories/GHSA-92g9-59rr-c…
- www.vulncheck.com/advisories/admidio-before-5.0.17-event-guest-…
- github.com/Admidio/admidio/security/advisories/GHSA-92g9-59rr-c…
Metrics
- CVSS 3.1
-
4.3
MEDIUM
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N - CVSS 4.0
-
5.3
MEDIUM
Score source: CNA
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 - EPSS — exploit probability
- 0% percentile: 22 · as of 8 November 2026
- CWE
- CWE-602
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.