Description
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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| mailcow | mailcow-dockerized | < 2026-03b | — |
Automated scanner template
A ready-made Nuclei template detects this vulnerability automatically. Vulnerabilities with public scanner templates are typically probed across the internet soon after the template appears — exposed systems should be patched first.
- Mailcow < 2026-03b - Href Link Injection http/cves/2026/CVE-2026-40878.yaml
Source: projectdiscovery/nuclei-templates (MIT) — updated daily. Only links are listed.