Vulnerability in Icewarp Mail Server

CVE-2025-40631

HTTP host header injection vulnerability in Icewarp Mail Server affecting version 11.4.0. By modifying the Host header and adding a payload, arbitrary JavaScript code can be executed on page load. The user must interact with a malicious li…

EPSS: 0.002 (8.1th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2025-40631?
CVE-2025-40631 is a medium-severity vulnerability in Icewarp Mail Server, classified under Improper Neutralization of HTTP Headers for Scripting Syntax. CVSS score: 6.1/10. Published 2025-05-16.
How severe is CVE-2025-40631?
Medium severity. CVSS v3 base score is 6.1 out of 10.
Is CVE-2025-40631 known to be exploited?
1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.