CVE-2025-53909: mailcow\ — Fix

Description

mailcow: dockerized is an open source groupware/email suite based on docker. A Server-Side Template Injection (SSTI) vulnerability exists in versions prior to 2025-07 in the notification template system used by mailcow for sending quota and quarantine alerts. The template rendering engine allows template expressions that may be abused to execute code in certain contexts. The issue requires admin-level access to mailcow UI to configure templates, which are automatically rendered during normal system operation. Version 2025-07 contains a patch for the issue.

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CVSS v3.1 Score

9.1

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

Weakness Type (CWE)

CWE-1336 CWE-1336

Affected Products

Vendor	Product	Versions
mailcow	mailcow\	< 2025-07

References

Advisories & Patches

https://github.com/mailcow/mailcow-dockerized/commit/8c5f6c03214a4b2bdbf3c78932f860eee949012b https://github.com/mailcow/mailcow-dockerized/security/advisories/GHSA-8p7g-6cjj-wr9m

Frequently Asked Questions

What is CVE-2025-53909? +

mailcow: dockerized is an open source groupware/email suite based on docker. A Server-Side Template Injection (SSTI) vulnerability exists in versions prior to 2025-07 in the notification template system used by mailcow for sending quota and quarantine alerts. The template rendering engine allows template expressions that may be abused to execute code in certain contexts. The issue requires admin-level access to mailcow UI to configure templates, which are automatically rendered during normal system operation. Version 2025-07 contains a patch for the issue. It has a CVSS v3.1 base score of 9.1 (CRITICAL).

How severe is CVE-2025-53909? +

CVE-2025-53909 has a CVSS v3.1 score of 9.1 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately.

What products are affected by CVE-2025-53909? +

CVE-2025-53909 affects products from mailcow, specifically: mailcow\. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-53909? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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