CVE-2026-19418: TYPO3 CMS

High severity, CVSS 7.3. EPSS: 0.2% chance of exploitation in the next 30 days.

The referrer enforcement introduced with TYPO3-CORE-SA-2020-006 (CVE-2020-11069) became ineffective in TYPO3 v13.0, where TYPO3 CMS started serving the backend and Install Tool applications from the site's main entry script instead of the dedicated typo3/ directory. Whether a request originated from the backend or Install Tool itself was determined by comparing the referrer against the directory of the entry script, which since then is the site root. As a consequence, requests originating from any script running on one of the TYPO3 instance's own domains, such as a frontend page, were accepted by backend routes and Install Tool endpoints. Attackers able to execute JavaScript on one of those domains, for instance by exploiting a cross-site scripting vulnerability, could invoke these endpoints via Fetch/XHR with the privileges of an authenticated victim's user session. This issue affects TYPO3 CMS versions 13.0.0-13.4.33 and 14.0.0-14.3.5.

Affected products

• TYPO3 TYPO3 CMS: from 13.0.0, before 13.4.34 (fixed in 13.4.34); from 14.0.0, before 14.3.6 (fixed in 14.3.6)

Published 2026-08-11. Last modified 2026-08-26.