CVE-2025-64999

7.3 highEPSS 0.2%

High (7.3) in checkmk checkmk. EPSS 0.2% chance of exploitation in the next 30 days.

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.

Severity

CVSS 4.0

7.3 high

CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:A/VC:H/VI:H/VA:H/SC:N/SI:L/SA:N

CVSS 3.1

5.4 medium

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

EPSS: 0.2% chance of exploitation in the next 30 days; higher than 6% of CVEs (scores of 2026-10-31)
CWE: CWE-79
Published: 2026-02-26
Modified: 2026-06-17
Record from: the NVD, synced 2026-10-19

Affected

checkmk:checkmk

References

https://checkmk.com/werk/19238
https://github.com/sbaresearch/advisories/tree/e72ce9bb6b9ffffc1fc35e4d8152ad153293c851/2025/SBA-ADV-20251118-01_Checkmk_Cross_Site_Scripting

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