TYPO3 is an enterprise content management system. Starting in version 9.0.0 and prior to versions 9.5.48 ELTS, 10.4.45 ELTS, 11.5.37 LTS, 12.4.15 LTS, and 13.1.1, failing to properly encode user-controlled values in file entities, the `ShowImageController` (`_eID tx_cms_showpic_`) is vulnerable to cross-site scripting. Exploiting this vulnerability requires a valid backend user account with access to file entities. TYPO3 versions 9.5.48 ELTS, 10.4.45 ELTS, 11.5.37 LTS, 12.4.15 LTS, 13.1.1 fix the problem described.
https://typo3.org/security/advisory/typo3-core-sa-2024-009
https://github.com/TYPO3/typo3/security/advisories/GHSA-hw6c-6gwq-3m3m
https://github.com/TYPO3/typo3/commit/d774642381354d3bf5095a5a26e18acd2767f0b1
https://github.com/TYPO3/typo3/commit/b31d05d1da3eeaeead2d19eb43b1c3f9c88e15ee
https://github.com/TYPO3/typo3/commit/376474904f6b9a54dc1b785a2e45277cbd13b0d7