Vulnerability advisory

GHSA-mfqj-cqv3-h7xw

TYPO3 CMS - Unrestricted File Upload in Form Framework

Published Aug 31, 2026Updated Aug 31, 2026OSV record ↗

Also known as CVE-2026-15305

Severity

CVSS 4.0CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N

Affected versions

typo3/cms-form Packagist

All typo3/cms-form advisories →

Affected	Fixed in
`14.2.0` to before 14.3.5	`14.3.5`Advisories →
Also listed as affected (6) `v14.2.0` `v14.3.0` `v14.3.1` `v14.3.2` `v14.3.3` `v14.3.4`

Description

Problem

Users were able to upload files with arbitrary MIME types to forms using FileUpload or ImageUpload elements with allowedMimeTypes configured - uploading PHP files was not possible. The restriction was not enforced server-side because the MimeTypeValidator was registered during form building before concrete form definition properties were applied, resulting in the validator never being added to the processing pipeline.

Solution

Update to TYPO3 version 14.3.5 LTS that fixes the problem described.

Credits

Thanks to Sébastien Convers for reporting this issue, and to Josua Vogel and Oliver Hader for fixing it.