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. This issue affects TYPO3 CMS versions before 10.4.57, 11.0.0-11.5.50, 12.0.0-12.4.45, 13.0.0-13.4.30 and 14.0.0-14.3.2.
https://typo3.org/security/advisory/typo3-core-sa-2026-008
https://github.com/TYPO3/typo3/commit/eb2b2251d90339d3ab55df3d4c0378ae0c780b45
https://github.com/TYPO3/typo3/commit/2030617e6f273cee7b756c695f0a48a45a31eb47
Published: 2026-06-09
Updated: 2026-06-09
Base Score: 6.5
Vector: CVSS2#AV:N/AC:L/Au:S/C:P/I:P/A:P
Severity: Medium
Base Score: 8.8
Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Severity: High
Base Score: 7.6
Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
Severity: High
EPSS: 0.0003