GHSA-JF56-V8JC-JCC5 TYPO3 CMS has Broken Access Control in its File Abstraction Layer

Problem The path allowance check in GeneralUtility::isAllowedAbsPath performed a plain string prefix comparison without requiring a directory separator boundary, causing a path like /var/www/html-other/secret.yaml to be incorrectly accepted as valid when the project root was /var/www/html...