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.
History

Wed, 22 Apr 2026 00:00:00 +0000

Type Values Removed Values Added
Description 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.
Title mailcow: dockerized vulnerable to stored XSS in user login history real_rip
Weaknesses CWE-79
CWE-80
References
Metrics cvssV4_0

{'score': 7, 'vector': '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'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-04-21T20:36:24.334Z

Reserved: 2026-04-15T15:57:41.718Z

Link: CVE-2026-40875

cve-icon Vulnrichment

Updated: 2026-04-21T19:53:12.403Z

cve-icon NVD

Status : Received

Published: 2026-04-21T20:17:01.120

Modified: 2026-04-21T21:16:43.477

Link: CVE-2026-40875

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.