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OpenAdvisories
High · 8.9 CVE-2026-40873 EUVD-2026-24255

mailcow: dockerized vulnerable to stored XSS in Quarantine attachment filenames

Published Apr 21, 2026 · Updated Apr 21, 2026 · Assigned by GitHub_M

Description

mailcow: dockerized is an open source groupware/email suite based on docker. In versions prior to 2026-03b, the Quarantine details modal injects attachment filenames into HTML without escaping, allowing arbitrary HTML/JS execution. An attacker can deliver an email with a crafted attachment name so that when an admin views the quarantine item, JavaScript executes in their browser, taking over their account. Version 2026-03b fixes the vulnerability.

Affected products

VendorProductAffectedFixed
mailcow mailcow-dockerized < 2026-03b —

References