CVE-2026-77129: TYPO3 Extension Event Management And Registration

High severity, CVSS 7.7. EPSS: 0.4% chance of exploitation in the next 30 days.

The extension passes an editor-configurable email subject string directly into a Fluid template source without restriction. A backend user with edit access to the event plugin or Backend Module can supply Fluid ViewHelper syntax in this field to disclose sensitive data or execute TypoScript content objects. Exploitation of this issue requires an authenticated backend account with edit access to the event registration plugin or backend module.

Affected products

• TYPO3 Extension Event Management And Registration: from 9.0.0, before 9.0.3 (fixed in 9.0.3); from 8.0.0, before 8.6.2 (fixed in 8.6.2); from 7.0.0, before 7.9.3 (fixed in 7.9.3); from 6.0.0, before 6.7.2 (fixed in 6.7.2); before 5.9.3 (fixed in 5.9.3)

Published 2026-08-25. Last modified 2026-08-26.