TYPO3 CMS has Broken Access Control in its Form Framework
### Problem Backend users with file write permissions were able to upload form definition files with mixed-case extensions (e.g., `.FORM.YAML`) to bypass the Form Framework's upload restriction. Maliciously crafted form definition files can be used to execute arbitrary SQL statements, allowing attackers to escalate privileges by creating administrative backend user accounts. ### 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 Alexander Künzl for reporting this issue, and to TYPO3 core & security team members Oliver Hader and Benjamin Franzke for fixing it. ### Resources * [TYPO3-CORE-SA-2026-008](https://typo3.org/security/advisory/typo3-core-sa-2026-008)
describes (1)
Related CVEs.
| ID | severity | exploitable | ||
|---|---|---|---|---|
| CVE-2026-47346US | —OT elevated | — | ||
Backend users with file write permissions were able to upload form definition files with mixed-case extensions (e.g., .FORM.YAML) to bypass the Form Framework's upload restriction.… | ||||
references
External citations — patches, advisories, analysis.
- https://github.com/FriendsOfPHP/security-advisories/blob/master/typo3/cms-core/CVE-2026-47346.yamlWEB
- https://github.com/TYPO3/typo3PACKAGE
- https://github.com/TYPO3/typo3/commit/2030617e6f273cee7b756c695f0a48a45a31eb47WEB
- https://github.com/TYPO3/typo3/commit/eb2b2251d90339d3ab55df3d4c0378ae0c780b45WEB
- https://github.com/TYPO3/typo3/security/advisories/GHSA-hwvq-2w67-rvxpWEB
- https://nvd.nist.gov/vuln/detail/CVE-2026-47346ADVISORY
- https://typo3.org/security/advisory/typo3-core-sa-2026-008WEB
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