What’s Vulnerable › Vulnerabilities

CVE-2026-40875: mailcow: dockerized vulnerable to stored XSS in user login history real_rip

• Severity: high (CVSS 7.0 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-04-21 · updated 2026-10-26
• Weakness: CWE-79

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.

Affected products

• mailcow-dockerized: before 2026-03b

References

• https://github.com/mailcow/mailcow-dockerized/security/advisories/GHSA-jprq-w83q-q62h
• https://github.com/mailcow/mailcow-dockerized/security/advisories/GHSA-jprq-w83q-q62h

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