TYPO3 CMS - Unrestricted File Upload in Form Framework

MEDIO 6.3CVE-2026-15305 · GHSA-mfqj-cqv3-h7xw · Published 14/07/2026 · updated 24/10/2026

En resumen

CVE-2026-15305 es una vulnerabilidad MEDIO (CVSS 6.3) que afecta a typo3/cms-form.
Probabilidad de explotación en los próximos 30 días (EPSS): 0.25%, mayor que el 16.9% de las vulnerabilidades.
Solución: actualizar a 14.3.5 o posterior.

Package	Affected versions	Patched versions
typo3/cms-form Packagist	`≥ 14.2.0, < 14.3.5`	`14.3.5`

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.

NVD description

Users were able to upload files with arbitrary MIME types to forms using FileUpload or ImageUpload elements with allowedMimeTypes configured. 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. This issue affects TYPO3 CMS versions 14.2.0-14.3.4.