CVE-2026-40874: Mailcow Mailcow-Dockerized

Medium severity, CVSS 6.0. EPSS: 0.3% chance of exploitation in the next 30 days.

mailcow: dockerized is an open source groupware/email suite based on docker. In versions prior to 2026-03b, no administrator verification takes place when deleting Forwarding Hosts with `/api/v1/delete/fwdhost`. Any authenticated user can call this API. Checks are only applied for edit/add actions, but deletion can still significantly disrupt the mail service. Version 2026-03b fixes the vulnerability.

Affected products

• Mailcow Mailcow-Dockerized: before 2026-03b (fixed in 2026-03b)

Published 2026-04-21. Last modified 2026-06-17.