CVE-2026-125757

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.

References

• https://github.com/mailcow/mailcow-dockerized/blob/55982ac74bfd35581cc44b122ab5fc659e3ae90a/data/conf/rspamd/lua/rspamd.local.lua#L847-L850
• https://github.com/mailcow/mailcow-dockerized/commit/e986803980db8b29435a2ddba5d9760737a818e3
• https://github.com/mailcow/mailcow-dockerized/releases/tag/2026-11
• https://github.com/mailcow/mailcow-dockerized/security/advisories/GHSA-jgr3-fv33-x43c
• https://www.vulncheck.com/advisories/mailcow-dockerized-before-2026-11-template-injection-rce-via-domain-wide-footer