CVE-2026-40875

published 2026-04-21

CVE-2026-40875: mailcow: dockerized is an open source groupware/email suite based on docker. In versions prior to 2026-03b, the user dashboard's "Seen successful connections"…

Priority P3 35 high 7 CVSS 4.0

AV N AC H AT P PR L UI P VC H VI N VA N SC H SI H SA N E X CR X IR X AR X MAV X MAC X MAT X MPR X MUI X MVC X MVI X MVA X MSC X MSI X MSA X S X AU X R X V X RE X U X

mailcow: dockerized is an open source groupware/email suite based on docker. In versions prior to 2026-03b, the user dashboard's "Seen successful connections" (login history) renders the client IP from login logs without HTML escaping. Because the server trusts the X-Real-IP header as the source IP for logging, an attacker can inject HTML/JS into this field. This Self-XSS can be exploited by a Login CSRF to force the victim into the attacker's account, and then read emails in a previous browser tab. Version 2026-03b fixes the vulnerability.

Affected

1 ranges

Vendor	Product	Version range	Fixed in
mailcow	mailcow-dockerized	< 2026-03b	2026-03b

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CWE-79 CWE-80