Is CVE-2026-40875 in the CISA KEV catalog?

No. CVE-2026-40875 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the EPSS score for CVE-2026-40875?

CVE-2026-40875 has an EPSS score of 0.18% (8th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix or mitigate CVE-2026-40875?

No published fix for CVE-2026-40875 has been found yet. Check the linked vendor advisories for guidance as it becomes available.

CVE & CISA-KEV Catalog

CVE-2026-40875

UNSCORED

NVD

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.

CWE-79Cross-Site Scripting (XSS)CWE-80

How to fix

No published remediation has been found for this vulnerability's affected products yet.

Mitigation guidance may be in the linked vendor advisories in the References section below.

CVSS v3.1 Vector

No CVSS vector data available.

Exploit Intelligence

0.18%probability of exploitation in 30 days

8thpercentile

Low risk: more likely to be exploited than 8% of all known CVEs.

References

Other references1

github.com

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-04-22.