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

> An admin can achieve remote code execution via Server-Side Template Injection in mailcow notification templates.

- **Severity:** Critical 9.1 (`CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 17 Jul 2025
- **Updated:** 17 Jul 2025
- **Also known as:** GHSA-8p7g-6cjj-wr9m

## What is CVE-2025-53909?

CVE-2025-53909 is a critical code injection vulnerability in mailcow-dockerized, published on 17 Jul 2025. An attacker needs administrator access to exploit it, with no action from the victim.

### Official 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.

Weakness: CWE-1336 (Improper Neutralization of Special Elements Used in a Template Engine)

## Which versions are affected by CVE-2025-53909?

It affects 1 product.


Products: Mailcow Mailcow\.

## How do I fix CVE-2025-53909?

No fix has been published for CVE-2025-53909 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-53909 being exploited?

There is no known exploitation of CVE-2025-53909 in the wild and no public exploit code.

## Other vulnerabilities in mailcow-dockerized

- [CVE-2024-24760](https://insights.sbomify.com/CVE-2024-24760/): Mailcow Docker Container Exposure to Local Network (high 8.8)
- [CVE-2023-34108](https://insights.sbomify.com/CVE-2023-34108/): Manipulation of Internal Dovecot Variables in mailcow via crafted Passwords (high 8.8)
- [CVE-2022-31138](https://insights.sbomify.com/CVE-2022-31138/): OS Command Injection in mailcow (high 8.8)
- [CVE-2022-31245](https://insights.sbomify.com/CVE-2022-31245/): Command injection in n/a (high 8.8)
- [CVE-2017-8928](https://insights.sbomify.com/CVE-2017-8928/): Cross-site request forgery in n/a (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-53909 and fix it if it is affected.

What it is: CVE-2025-53909 is a critical code injection vulnerability in mailcow-dockerized, published on 17 Jul 2025. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-53909 in the wild and no public exploit code.

Affected product: mailcow-dockerized. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2025-53909/ (Markdown: https://insights.sbomify.com/CVE-2025-53909/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-53909
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-53909
- OSV: https://osv.dev/vulnerability/CVE-2025-53909

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-53909/
Summaries are generated and may contain mistakes; the official description above is the record.