CVE-2026-40878
mailcow-dockerized Login Page has Reflected Parameter Injection / Wrong-Context XSS Escaping
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in 2026-03b
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- 1 Nuclei template
CISA's decision points: whether it is exploited, whether attacks can be automated, and how much control an attacker gets. Assessed (SSVC 2.0.3).What do these mean? →
- Exploitation: none
- Automatable: no
- Technical impact: partial
Summary
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.
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: none · Automatable: no · Technical impact: partial
- Record last updated
Affected versions
- mailcow mailcow-dockerized
fixed in 2026-03b