mailcow: dockerized vulnerable to SSTI in Quota and Quarantine Notification Template

published 2025-07-17 15 mo ago modified 2026-06-17 4 mo ago also EUVD-2025-21774

cvss: 9.1; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.5%; EPSS 0.5% chance of exploitation in 30 days, percentile 45%
public exploits: 0; none known

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.

Patch / fix

fixed in 1 links 1

mailcow mailcow:_dockerized 2025-07

github.com/mailcow/mailcow-dockerized@8c5f6c0 commit

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 15 mo ago (2025-07-17)

Exploit prediction

0.54% chance of exploitation in the next 30 days, higher than 45% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	9.1	CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
NVD	3.1	7.2	CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

Affected products

mailcow mailcow-dockerized

Classification

Weakness

CWE-1336 Improper Neutralization of Special Elements Used in a Template Engine

References

Sources

CVE List CVE-2025-53909
NVD CVE-2025-53909

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.

Summary