CVE-2025-39663

high-risk
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).

Do I need to act?

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0.06% chance of exploitation
EPSS score — low exploit probability
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Not on CISA KEV list
No confirmed active exploitation reported to CISA
?
Patch status unknown
Check vendor advisories for fix availability and mitigation guidance
8
CVSS 8.4/10 High
NETWORK / LOW complexity

Affected Vendors

55
/ 100
high-risk
Severity 29/34 · Critical
Exploitability 0/34 · Minimal
Exposure 26/34 · High