Description
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.
References (2)
Core 2
Core References
Various Sources vendor-advisory
https://checkmk.com/werk/19238
Third Party Advisory third-party-advisory
https://github.com/sbaresearch/advisories/tree/e72ce9bb6b9ffffc1fc35e4d8152ad153293c851/2025/SBA-ADV-20251118-01_Checkmk_Cross_Site_Scripting
Scores
CVSS v3
5.4
EPSS
0.0003
EPSS Percentile
10.3%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
CISA SSVC
Vulnrichment
Exploitation
poc
Automatable
no
Technical Impact
total
Details
CWE
CWE-79
Status
published
Products (2)
checkmk/checkmk
2.3.0 (49 CPE variants)
checkmk/checkmk
2.4.0
Published
Feb 26, 2026
Tracked Since
Feb 26, 2026