CVE-2025-64999

Cross-site scripting in HTML logs of Synthetic Monitoring test services

Published Feb 26, 2026 CVSS 4.0 · 7.3 High EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
CPEs cpe:2.3:a:checkmk:checkmk:2.3.0:-:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:b1:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:b2:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:b3:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:b4:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:b5:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:b6:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p10:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p11:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p12:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p13:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p14:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p15:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p16:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p17:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p18:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p19:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p1:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p20:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p21:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p22:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p23:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p24:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p25:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p26:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p27:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p28:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p29:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p2:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p30:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p31:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p32:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p33:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p34:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p35:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p36:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p37:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p38:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p39:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p3:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p40:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p41:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p42:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p4:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p5:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p6:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p7:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p8:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.3.0:p9:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:-:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:b1:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:b2:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:b3:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:b4:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:b5:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:b6:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:p10:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:p11:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:p12:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:p13:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:p14:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:p15:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:p16:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:p17:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:p18:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:p19:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:p1:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:p20:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:p21:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:p2:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:p3:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:p4:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:p5:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:p6:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:p7:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:p8:*:*:*:*:*:*
cpe:2.3:a:checkmk:checkmk:2.4.0:p9:*:*:*:*:*:*
Metrics cvssV3_1

{'score': 5.4, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N'}

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
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.
Title Cross-site scripting in HTML logs of Synthetic Monitoring test services
First Time appeared Checkmk
Checkmk checkmk
Weaknesses CWE-79
CPEs cpe:2.3:a:checkmk:checkmk:*:*:*:*:*:*:*:*
Vendors & Products Checkmk
Checkmk checkmk
References
Metrics cvssV4_0

{'score': 7.3, 'vector': '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'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
Checkmk
Published
Updated
Apr 14, 2026, 2:28 PM
Reserved
Nov 12, 2025, 9:16 AM
Status
Modified
Published
Feb 26, 2026, 11:16 AM
Modified
Jun 17, 2026, 9:55 AM