CVE-2026-40878

mailcow: dockerized is an open source groupware/email suite based on docker. In versions prior to 2026-03b, the mailcow web interface passes the raw `$_SERVER['REQUEST_URI']` to Twig as a global template variable and renders it inside a JavaScript string literal in the `setLang()` helper of `base.twig`, relying on Twig's default HTML auto-escaping instead of the context-appropriate `js` escaping strategy. In addition, the `query_string()` Twig helper merges all current `$_GET` parameters into the language-switching links on the login page, so attacker-supplied parameters are reflected and preserved across navigation. Version 2026-03b fixes the vulnerability.

The following products are affected by CVE-2026-40878 vulnerability.

Here, you will find a curated list of external links that provide in-depth information to CVE-2026-40878.

URL	Resource
https://github.com/mailcow/mailcow-dockerized/security/advisories/GHSA-xv9r-j862-5hqf