CVE-2026-117554 PUBLISHED

Admidio before 5.0.17 Event Guest Restriction Bypass via events_function.php

Assigner: VulnCheck
Reserved: 27.10.2026 Published: 27.10.2026 Updated: 27.10.2026

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.

CVSS Vector: 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
CVSS Score: 5.3

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	None	Confidentiality	None
Attack Complexity	Low	Integrity	Low	Integrity	None
Attack Requirements	None	Availability	None	Availability	None
Privileges Required	Low
User Interaction	None

CVSS 4.0

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
CVSS Score: 4.3

Attack Vector	Network	Scope	Unchanged
Attack Complexity	Low	Confidentiality Impact	None
Privileges Required	Low	Integrity Impact	Low
User Interaction	None	Availability Impact	None

CVSS 3.1

Product Status

Vendor	admidio
Product	admidio
Versions	Default: unaffected affected from 0 to 5.0.17 (excl.)

Credits

gwangwon0807 finder
choewonwoo1817 finder
J0hnathanKim finder
Kamba-netizen finder
t-211 finder
xo0102 finder
Fasse remediation developer

References

Problem Types

Client-Side Enforcement of Server-Side Security CWE