# CVE-2025-39663: Cross-Site Scripting (XSS) vulnerability in Checkmk's distributed monitoring allows a compromised remote site to…

Source: https://junglewise.ai/threats/cve-2025-39663-cross-site-scripting-xss-vulnerability-in-checkmk-s-distributed  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2025-10-30  
License: CC BY 4.0 with a link back

CVE-2025-39663 · Severity: high · CVSS 8.4 · Published 2025-10-30

Cross-Site Scripting (XSS) vulnerability in Checkmk's distributed monitoring allows a compromised remote site to inject malicious HTML code into service outputs in the central site. Affecting Checkmk before 2.4.0p14, 2.3.0p39, 2.2.0 and 2.1.0 (eol).

Technologies: [Checkmk](https://junglewise.ai/threats/technologies/checkmk). Vendors: [Checkmk](https://junglewise.ai/threats/vendors/checkmk).

## Quick answers

**Is CVE-2025-39663 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2025-39663 being exploited in the wild.

**How severe is CVE-2025-39663?** High severity, with a CVSS score of 8.4, published 30 October 2025.

**Which products and versions are affected?** Checkmk. The advisory does not name versions.

**Is there a fix for CVE-2025-39663?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**Am I affected by CVE-2025-39663?** Check whether you run Checkmk. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Affected products

- Checkmk

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