---
id: "CVE-2026-125757"
page: "https://infrastack.ai/live/CVE-2026-125757"
kind: "vulnerability"
aliases: ["CVE-2026-125757"]
title: "mailcow: domain admins can run commands in shared rspamd container"
severity: "critical"
cvss: 9.4
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["mailcow", "email", "poc-public", "rspamd", "package", "self-hosted"]
not_affected_if: ["mailcow-at-or-above-2026-11", "single-tenant"]
published_at: "2026-11-10T16:17:23+00:00"
first_seen_at: "2026-11-10T16:22:35+00:00"
updated_at: "2026-11-10T16:39:55+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-125757", "first_seen_at": "2026-11-10T16:22:35+00:00"}, {"source": "github-poc", "url": "https://github.com/Faceless0x7/CVE-2026-125757", "first_seen_at": "2026-11-10T16:39:55+00:00"}]
exploit_sources: [{"type": "poc", "url": "https://github.com/Faceless0x7/CVE-2026-125757"}]
---

# mailcow: domain admins can run commands in shared rspamd container

Link for people: https://infrastack.ai/live/CVE-2026-125757 (this .md is for agents)

mailcow dockerized before 2026-11 lets a domain administrator store a malicious domain-wide footer that is rendered as a Jinja template by the rspamd filter. The attacker can run commands in the shared rspamd container, read or inject mail for every tenant, and disable spam filtering.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the mailcow version in the installed mailcow-dockerized repository (unknown exact command in sources)
- Confirm whether the installation is below `2026-11`
- Review domain footer settings for untrusted domain administrators

## Fix

- mailcow dockerized: move to `2026-11` or later (per the sources' 'before 2026-11' range)

## Timeline

- 2026-11-10T16:22:35+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-125757
- 2026-11-10T16:39:55+00:00 github-poc https://github.com/Faceless0x7/CVE-2026-125757

## Documents

- [advisory] Vendor advisory: github.com https://github.com/mailcow/mailcow-dockerized/security/advisories/GHSA-jgr3-fv33-x43c
- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/mailcow-dockerized-before-2026-11-template-injection-rce-via-domain-wide-footer
- [fix] Patch: github.com https://github.com/mailcow/mailcow-dockerized/commit/e986803980db8b29435a2ddba5d9760737a818e3
- [fix] Release notes: github.com https://github.com/mailcow/mailcow-dockerized/releases/tag/2026-11
- [poc] Faceless0x7/CVE-2026-125757 https://github.com/Faceless0x7/CVE-2026-125757

## From the sources

mailcow: dockerized before 2026-11 contains a server-side template injection vulnerability that allows domain administrators to execute commands in the shared rspamd container by storing a malicious domain-wide footer. Attackers can embed a Jinja macro with an os.execute default value, rendered by the rspamd MOO_FOOTER prefilter, to read or inject mail for every tenant and disable filtering.

---

_Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai_