CVE-2025-64999

moderate-risk
Published 2026-02-26

Improper neutralization of input in Checkmk versions 2.4.0 before 2.4.0p22, and 2.3.0 before 2.3.0p43 allows an attacker that can manipulate a host's check output to inject malicious JavaScript into the Synthetic Monitoring HTML logs, which can then be accessed via a crafted phishing link.

Do I need to act?

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0.03% 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
5
CVSS 5.4/10 Medium
NETWORK / LOW complexity

Affected Vendors

49
/ 100
moderate-risk
Severity 21/34 · High
Exploitability 0/34 · Minimal
Exposure 28/34 · Critical