🚨 CVE-2026-15305
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.
🎖@cveNotify
GitHub
[SECURITY] Register MimeTypeValidator for file uploads at runtime · TYPO3/typo3@817ad41
The "allowedMimeTypes" restriction of the FileUpload and ImageUpload
form elements was never enforced on the server side. Uploading a file
whose MIME type is not part of the confi...
September 3, 2026 43
