TYPO3 is an open source web content management system. Prior to versions 9.5.34 ELTS, 10.4.29, and 11.5.11, Admin Tool sessions initiated via the TYPO3 backend user interface had not been revoked even if the corresponding user account was degraded to lower permissions or disabled completely. This way, sessions in the admin tool theoretically could have been prolonged without any limit. TYPO3 versions 9.5.34 ELTS, 10.4.29, and 11.5.11 contain a fix for the problem.