# CVE-2026-120331: TYPO3 Mail extension server-side request forgery

Source: https://junglewise.ai/threats/cve-2026-120331-content-of-external-url-mails-their-stylesheets-and-images-to  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-03. Updated: 2026-11-03  
License: CC BY 4.0 with a link back

CVE-2026-120331 · Severity: info · Published 2026-11-03

The Mail extension for TYPO3, a content management system widely used for websites, fetches external content like stylesheets and images from URLs without validating whether those URLs point to internal network hosts. A backend user with mail module access can manipulate this to make the server send requests to internal systems, potentially exposing sensitive data or accessing restricted resources.

Vendors: [Typo3](https://junglewise.ai/threats/vendors/typo3).

## Quick answers

**Is CVE-2026-120331 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-120331 being exploited in the wild.

**How severe is CVE-2026-120331?** Informational severity, published 3 November 2026.

**Which products and versions are affected?** Typo3 Mail extension 3.12.4 and below, 4.0.0–4.1.0.

**Is there a fix for CVE-2026-120331?** Yes: fixed in 3.12.5, 4.2.0. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-120331 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-120331?** Check whether you run Typo3 Mail extension at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in 3.12.5, 4.2.0

## Technical details

The Mail extension fails to validate target hosts when fetching external URL content, stylesheets, and images for emails, enabling server-side request forgery (SSRF). An authenticated backend user with access to the mail module can exploit this to send requests to internal network hosts. The vulnerability affects versions 3.12.4 and below, and 4.0.0–4.1.0; patches are available in 3.12.5 and 4.2.0.

## Affected products

- TYPO3 Mail extension 3.12.4 and below, 4.0.0–4.1.0

## Timeline

- 2026-11-03: disclosed

## References

- [https://packagist.org/](https://packagist.org/)
- [https://typo3.org/security/advisory/typo3-ext-sa-2026-037](https://typo3.org/security/advisory/typo3-ext-sa-2026-037)

## Related threats

- [TYPO3 Mail extension arbitrary page TSconfig write](https://junglewise.ai/threats/cve-2026-120329-saving-the-configuration-of-the-mail-backend-module-writes)