CVE-2021-21370: TYPO3

Medium severity, CVSS 5.4. EPSS: 0.9% chance of exploitation in the next 30 days.

TYPO3 is an open source PHP based web content management system. In TYPO3 before versions 7.6.51, 8.7.40, 9.5.25, 10.4.14, 11.1.1 it has been discovered that content elements of type _menu_ are vulnerable to cross-site scripting when their referenced items get previewed in the page module. A valid backend user account is needed to exploit this vulnerability. This is fixed in versions 7.6.51, 8.7.40, 9.5.25, 10.4.14, 11.1.1.

Affected products

• TYPO3 TYPO3: from 7.0.0, before 7.6.51 (fixed in 7.6.51); from 8.0.0, before 8.7.40 (fixed in 8.7.40); from 9.0.0, before 9.5.25 (fixed in 9.5.25); from 10.0.0, before 10.4.14 (fixed in 10.4.14); from 11.0.0, before 11.1.1 (fixed in 11.1.1)

Published 2021-03-23. Last modified 2026-06-17.