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`. Administrator users with access to the File Abstraction Layer were able to create new file storage definitions pointing to directories outside the project root, bypassing this path check. ### Solution Update to TYPO3 versions 10.4.57 ELTS, 11.5.51 ELTS, 12.4.46 ELTS, 13.4.31 LTS, 14.3.3 LTS that fix the problem described. ### Credits TYPO3 CMS thanks Wolfgang Klinger for reporting this issue, and to TYPO3 core & security team member Oliver Hader for fixing it. ### Resources * [TYPO3-CORE-SA-2026-016](https://typo3.org/security/advisory/typo3-core-sa-2026-016)
describes (1)
Related CVEs.
| ID | severity | exploitable | ||
|---|---|---|---|---|
| CVE-2026-49738US | — | — | ||
The path allowance check in GeneralUtility::isAllowedAbsPath() performed a plain string prefix comparison without requiring a directory separator boundary, causing a path like /var… | ||||
references
External citations — patches, advisories, analysis.
- https://github.com/FriendsOfPHP/security-advisories/blob/master/typo3/cms-core/CVE-2026-49738.yamlWEB
- https://github.com/TYPO3/typo3PACKAGE
- https://github.com/TYPO3/typo3/commit/150a983a5d687cedcfc33bbe9c335d9a13fd05e5WEB
- https://github.com/TYPO3/typo3/commit/44c2fa9807944136218a0842e3051c0a379a002dWEB
- https://github.com/TYPO3/typo3/security/advisories/GHSA-jf56-v8jc-jcc5WEB
- https://nvd.nist.gov/vuln/detail/CVE-2026-49738ADVISORY
- https://typo3.org/security/advisory/typo3-core-sa-2026-016WEB
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