🛡️ CVE-2025-53909 — mailcow\

🔴 CVSS 9.1 — Critical ✅ No Known Exploit CWE-1336 NVD
9.1
CVSS Score
0 Low4 Medium7 High9 Critical10

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.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs administrative privileges on the target. No user interaction is required. The scope is changed, meaning a successful attack can affect components beyond the vulnerable one. Rated impact: confidentiality high, integrity high, availability high.

Weakness class

CVE-2025-53909 is classified as CWE-1336: Improper Neutralization of Special Elements Used in a Template Engine. The product uses a template engine to insert or process externally-influenced input, but it does not neutralize or incorrectly neutralizes special elements or syntax that can be interpreted as template expressions or other code directives when…

Affected software

CVE-2025-53909 is recorded against 1 package.

  • mailcow\ (fixed in 2025-07)

Timeline and source

Published on 17 July 2025 and last revised on 17 June 2026. No public exploit is currently recorded for this entry. A vendor advisory or fix has been published. Record sourced from NVD.

References

github.com
github.com

Details

Severity CRITICAL
CVSS Score 9.1
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
CWE CWE-1336
Public Exploit ✅ No
Source NVD
Published 2025-07-17
Updated 2026-08-11
Modified 2026-06-17

Affected Packages

Software From version Fixed in
mailcow\ — 2025-07

Exploit Protection

Are you running mailcow\?

CVE-2025-53909 carries CVSS 9.1 Critical rating. BotEraser checks your installation against this and other known CVE records, and blocks IPs associated with exploit activity.

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