CVE-2026-40871

mailcow: dockerized is an open source groupware/email suite based on docker. Versions prior to 2026-03b have a second-order SQL injection vulnerability in the quarantine_category field via the Mailcow API. The /api/v1/add/mailbox endpoint stores quarantine_category without validation or sanitization. This value is later used by quarantine_notify.py, which constructs SQL queries using unsafe % string formatting instead of parameterized queries. This results in a delayed (second-order) SQL injection when the quarantine notification job executes, allowing an attacker to inject arbitrary SQL. Using a UNION SELECT, sensitive data (e.g., admin credentials) can be exfiltrated and rendered inside quarantine notification emails. Version 2026-03b fixes the vulnerability.

The following products are affected by CVE-2026-40871 vulnerability.

Here, you will find a curated list of external links that provide in-depth information to CVE-2026-40871.

URL	Resource
https://github.com/mailcow/mailcow-dockerized/security/advisories/GHSA-r8fq-wrfm-cj2q