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Public proof of conceptAwaiting NVD analysis

CVE-2026-125757

mailcow: dockerized before 2026-11 Template Injection RCE via Domain-Wide Footer

A public proof of concept exists; no exploitation attested.

  • Published2026-11-10
  • WeaknessCWE-1336

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

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.

Timeline

dates in UTC
  1. 2026-11-1015:22CVE publishedCNA

Versions per branch

Products declared by the CNA

As VulnCheck, the CNA that assigned this CVE, declared them in the CVE record; versions as written. NVD lists no product for this CVE yet: this is the only product data so far.

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2026-11-10

Neither OSV.dev nor the vendor advisories we read list affected versions for CVE-2026-125757 yet.

Full record on NVD

Fix

No fix published by the sources we read yet. NVD record

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

  • NVDCVE record2026-11-10
  • CISA-ADPSSVC decisionpoc2026-11-10
  • CNACVSS 4.09.42026-11-10
  • CNACVSS 3.19.12026-11-10
  • CNAweakness (CWE)CWE-13362026-11-10

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
CVSS 4.0 vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
Published
2026-11-10

Frequently asked questions

What is CVE-2026-125757?

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.

Is CVE-2026-125757 actively exploited?

A proof-of-concept exploit exists for CVE-2026-125757, but active exploitation has not been confirmed at this time.

What is the CVSS score for CVE-2026-125757?

CVE-2026-125757 has a CVSS v3 base score of 9.1 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H.

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