CVE-2025-53909: mailcow: dockerized is an open source groupware/email suite based on docker

Q: How do I fix CVE-2025-53909?

mailcow\: upgrade to 2025-07. Exact commands for each OS are on this page.

Q: Is CVE-2025-53909 being exploited?

CVE-2025-53909 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2025-53909 affect?

CVE-2025-53909 affects mailcow\. Severity is critical (CVSS 9.1). 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

Q: How urgent is CVE-2025-53909?

Priority 48/100. Critical severity; On your watchlist

This month

CRITICAL 9.1WATCHLISTUPGRADE

CVE-2025-53909 is a critical-severity flaw (CVSS 9.1) affecting mailcow\. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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,

Why this priority

Critical severity
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	9.1 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	High
User interaction	None
EPSS exploit chance	0.5% (top 55%)
CISA exploited list	No
Weakness	CWE-1336
Published	2025-07-17
Last modified	2026-06-17

Publisher (CNA): GitHub, Inc. · Vendor: mailcow

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2025-07-17 14:15 UTCPublished CVE record published
2026-06-17 09:39 UTCUpdated Record last modified

mailcow mailcow\ UPGRADE

Affected: < 2025-07

Fixed in: 2025-07

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy mailcow || rpm -q mailcow || mailcow --version

2. UPGRADE to 2025-07 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade mailcow

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade mailcow

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2025-53909?

mailcow\: upgrade to 2025-07. Exact commands for each OS are on this page.

Is CVE-2025-53909 being exploited?

CVE-2025-53909 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2025-53909 affect?

CVE-2025-53909 affects mailcow\. Severity is critical (CVSS 9.1). 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

How urgent is CVE-2025-53909?

Priority 48/100. Critical severity; On your watchlist

Software pages

Docker vulnerabilities

Related CVEs

CVE-2025-25198 HIGH 7.1 UPGRADE mailcow: dockerized is an open source groupware/email suite based on docker
CVE-2024-41960 LOW 3.8 UPGRADE mailcow: dockerized is an open source groupware/email suite based on docker
CVE-2024-41959 HIGH 7.6 UPGRADE mailcow: dockerized is an open source groupware/email suite based on docker
CVE-2024-41958 MEDIUM 6.6 UPGRADE mailcow: dockerized is an open source groupware/email suite based on docker

References

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