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TI-2025-26345 Aliases CVE-2025-39663GHSA-m8fq-fxf8-wxx3

Cross Site Scripting through compromised remote site

Priority HIGH 72CWE-80Published · Updated

Key facts

Attack vector
Network
Privileges required
High
User interaction
Passive
Attack complexity
Low
Attack requirements
None
Impact type
Cross-site scripting
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-80.

Summary

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).

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00603 49th percentileScored 2026-11-07
Public exploit Yes 2 exploit referencesTagged by NVD
Fix Fixed Checkmk (Checkmk GmbH): 2.4.0p14, 2.3.0p39

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
Checkmk GmbHCheckmk2.4.0 to before 2.4.0p14; 2.3.0 to before 2.3.0p39; 2.2.0; 2.1.02.4.0p14, 2.3.0p39Patch availableCNA
  • Checkmk VendorCheckmk GmbH Affected 2.4.0 to before 2.4.0p14; 2.3.0 to before 2.3.0p39; 2.2.0; 2.1.0 Fixed in 2.4.0p14, 2.3.0p39 Patch available CNA

CPE configurations NVD · 53

CPEVersionsRoleVendor
cpe:2.3:a:checkmk:checkmk:*:*:*:*:*:*:*:*2.0.0 to before 2.3.0VulnerableCheckmk GmbH
cpe:2.3:a:checkmk:checkmk:2.3.0:-:*:*:*:*:*:*2.3.0VulnerableCheckmk GmbH
cpe:2.3:a:checkmk:checkmk:2.3.0:p1:*:*:*:*:*:*2.3.0 p1VulnerableCheckmk GmbH
cpe:2.3:a:checkmk:checkmk:2.3.0:p10:*:*:*:*:*:*2.3.0 p10VulnerableCheckmk GmbH
cpe:2.3:a:checkmk:checkmk:2.3.0:p11:*:*:*:*:*:*2.3.0 p11VulnerableCheckmk GmbH
cpe:2.3:a:checkmk:checkmk:2.3.0:p12:*:*:*:*:*:*2.3.0 p12VulnerableCheckmk GmbH
cpe:2.3:a:checkmk:checkmk:2.3.0:p13:*:*:*:*:*:*2.3.0 p13VulnerableCheckmk GmbH
cpe:2.3:a:checkmk:checkmk:2.3.0:p14:*:*:*:*:*:*2.3.0 p14VulnerableCheckmk GmbH
cpe:2.3:a:checkmk:checkmk:2.3.0:p15:*:*:*:*:*:*2.3.0 p15VulnerableCheckmk GmbH
cpe:2.3:a:checkmk:checkmk:2.3.0:p16:*:*:*:*:*:*2.3.0 p16VulnerableCheckmk GmbH
  • cpe:2.3:a:checkmk:checkmk:*:*:*:*:*:*:*:* Versions 2.0.0 to before 2.3.0 Vulnerable ·Checkmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.3.0:-:*:*:*:*:*:* Versions 2.3.0 Vulnerable ·Checkmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.3.0:p1:*:*:*:*:*:* Versions 2.3.0 p1 Vulnerable ·Checkmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.3.0:p10:*:*:*:*:*:* Versions 2.3.0 p10 Vulnerable ·Checkmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.3.0:p11:*:*:*:*:*:* Versions 2.3.0 p11 Vulnerable ·Checkmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.3.0:p12:*:*:*:*:*:* Versions 2.3.0 p12 Vulnerable ·Checkmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.3.0:p13:*:*:*:*:*:* Versions 2.3.0 p13 Vulnerable ·Checkmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.3.0:p14:*:*:*:*:*:* Versions 2.3.0 p14 Vulnerable ·Checkmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.3.0:p15:*:*:*:*:*:* Versions 2.3.0 p15 Vulnerable ·Checkmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.3.0:p16:*:*:*:*:*:* Versions 2.3.0 p16 Vulnerable ·Checkmk GmbH
Show 43 more CPE
CPEVersionsRoleVendor
cpe:2.3:a:checkmk:checkmk:2.3.0:p17:*:*:*:*:*:*2.3.0 p17VulnerableCheckmk GmbH
cpe:2.3:a:checkmk:checkmk:2.3.0:p18:*:*:*:*:*:*2.3.0 p18VulnerableCheckmk GmbH
cpe:2.3:a:checkmk:checkmk:2.3.0:p19:*:*:*:*:*:*2.3.0 p19VulnerableCheckmk GmbH
cpe:2.3:a:checkmk:checkmk:2.3.0:p2:*:*:*:*:*:*2.3.0 p2VulnerableCheckmk GmbH
cpe:2.3:a:checkmk:checkmk:2.3.0:p20:*:*:*:*:*:*2.3.0 p20VulnerableCheckmk GmbH
cpe:2.3:a:checkmk:checkmk:2.3.0:p21:*:*:*:*:*:*2.3.0 p21VulnerableCheckmk GmbH
cpe:2.3:a:checkmk:checkmk:2.3.0:p22:*:*:*:*:*:*2.3.0 p22VulnerableCheckmk GmbH
cpe:2.3:a:checkmk:checkmk:2.3.0:p23:*:*:*:*:*:*2.3.0 p23VulnerableCheckmk GmbH
cpe:2.3:a:checkmk:checkmk:2.3.0:p24:*:*:*:*:*:*2.3.0 p24VulnerableCheckmk GmbH
cpe:2.3:a:checkmk:checkmk:2.3.0:p25:*:*:*:*:*:*2.3.0 p25VulnerableCheckmk GmbH
cpe:2.3:a:checkmk:checkmk:2.3.0:p26:*:*:*:*:*:*2.3.0 p26VulnerableCheckmk GmbH
cpe:2.3:a:checkmk:checkmk:2.3.0:p27:*:*:*:*:*:*2.3.0 p27VulnerableCheckmk GmbH
cpe:2.3:a:checkmk:checkmk:2.3.0:p28:*:*:*:*:*:*2.3.0 p28VulnerableCheckmk GmbH
cpe:2.3:a:checkmk:checkmk:2.3.0:p29:*:*:*:*:*:*2.3.0 p29VulnerableCheckmk GmbH
cpe:2.3:a:checkmk:checkmk:2.3.0:p3:*:*:*:*:*:*2.3.0 p3VulnerableCheckmk GmbH
cpe:2.3:a:checkmk:checkmk:2.3.0:p30:*:*:*:*:*:*2.3.0 p30VulnerableCheckmk GmbH
cpe:2.3:a:checkmk:checkmk:2.3.0:p31:*:*:*:*:*:*2.3.0 p31VulnerableCheckmk GmbH
cpe:2.3:a:checkmk:checkmk:2.3.0:p32:*:*:*:*:*:*2.3.0 p32VulnerableCheckmk GmbH
cpe:2.3:a:checkmk:checkmk:2.3.0:p33:*:*:*:*:*:*2.3.0 p33VulnerableCheckmk GmbH
cpe:2.3:a:checkmk:checkmk:2.3.0:p34:*:*:*:*:*:*2.3.0 p34VulnerableCheckmk GmbH
cpe:2.3:a:checkmk:checkmk:2.3.0:p35:*:*:*:*:*:*2.3.0 p35VulnerableCheckmk GmbH
cpe:2.3:a:checkmk:checkmk:2.3.0:p36:*:*:*:*:*:*2.3.0 p36VulnerableCheckmk GmbH
cpe:2.3:a:checkmk:checkmk:2.3.0:p37:*:*:*:*:*:*2.3.0 p37VulnerableCheckmk GmbH
cpe:2.3:a:checkmk:checkmk:2.3.0:p38:*:*:*:*:*:*2.3.0 p38VulnerableCheckmk GmbH
cpe:2.3:a:checkmk:checkmk:2.3.0:p4:*:*:*:*:*:*2.3.0 p4VulnerableCheckmk GmbH
cpe:2.3:a:checkmk:checkmk:2.3.0:p5:*:*:*:*:*:*2.3.0 p5VulnerableCheckmk GmbH
cpe:2.3:a:checkmk:checkmk:2.3.0:p6:*:*:*:*:*:*2.3.0 p6VulnerableCheckmk GmbH
cpe:2.3:a:checkmk:checkmk:2.3.0:p7:*:*:*:*:*:*2.3.0 p7VulnerableCheckmk GmbH
cpe:2.3:a:checkmk:checkmk:2.3.0:p8:*:*:*:*:*:*2.3.0 p8VulnerableCheckmk GmbH
cpe:2.3:a:checkmk:checkmk:2.3.0:p9:*:*:*:*:*:*2.3.0 p9VulnerableCheckmk GmbH
cpe:2.3:a:checkmk:checkmk:2.4.0:-:*:*:*:*:*:*2.4.0VulnerableCheckmk GmbH
cpe:2.3:a:checkmk:checkmk:2.4.0:p1:*:*:*:*:*:*2.4.0 p1VulnerableCheckmk GmbH
cpe:2.3:a:checkmk:checkmk:2.4.0:p10:*:*:*:*:*:*2.4.0 p10VulnerableCheckmk GmbH
cpe:2.3:a:checkmk:checkmk:2.4.0:p11:*:*:*:*:*:*2.4.0 p11VulnerableCheckmk GmbH
cpe:2.3:a:checkmk:checkmk:2.4.0:p12:*:*:*:*:*:*2.4.0 p12VulnerableCheckmk GmbH
cpe:2.3:a:checkmk:checkmk:2.4.0:p13:*:*:*:*:*:*2.4.0 p13VulnerableCheckmk GmbH
cpe:2.3:a:checkmk:checkmk:2.4.0:p2:*:*:*:*:*:*2.4.0 p2VulnerableCheckmk GmbH
cpe:2.3:a:checkmk:checkmk:2.4.0:p3:*:*:*:*:*:*2.4.0 p3VulnerableCheckmk GmbH
cpe:2.3:a:checkmk:checkmk:2.4.0:p4:*:*:*:*:*:*2.4.0 p4VulnerableCheckmk GmbH
cpe:2.3:a:checkmk:checkmk:2.4.0:p5:*:*:*:*:*:*2.4.0 p5VulnerableCheckmk GmbH
cpe:2.3:a:checkmk:checkmk:2.4.0:p6:*:*:*:*:*:*2.4.0 p6VulnerableCheckmk GmbH
cpe:2.3:a:checkmk:checkmk:2.4.0:p7:*:*:*:*:*:*2.4.0 p7VulnerableCheckmk GmbH
cpe:2.3:a:checkmk:checkmk:2.4.0:p9:*:*:*:*:*:*2.4.0 p9VulnerableCheckmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.3.0:p17:*:*:*:*:*:* Versions 2.3.0 p17 Vulnerable ·Checkmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.3.0:p18:*:*:*:*:*:* Versions 2.3.0 p18 Vulnerable ·Checkmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.3.0:p19:*:*:*:*:*:* Versions 2.3.0 p19 Vulnerable ·Checkmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.3.0:p2:*:*:*:*:*:* Versions 2.3.0 p2 Vulnerable ·Checkmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.3.0:p20:*:*:*:*:*:* Versions 2.3.0 p20 Vulnerable ·Checkmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.3.0:p21:*:*:*:*:*:* Versions 2.3.0 p21 Vulnerable ·Checkmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.3.0:p22:*:*:*:*:*:* Versions 2.3.0 p22 Vulnerable ·Checkmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.3.0:p23:*:*:*:*:*:* Versions 2.3.0 p23 Vulnerable ·Checkmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.3.0:p24:*:*:*:*:*:* Versions 2.3.0 p24 Vulnerable ·Checkmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.3.0:p25:*:*:*:*:*:* Versions 2.3.0 p25 Vulnerable ·Checkmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.3.0:p26:*:*:*:*:*:* Versions 2.3.0 p26 Vulnerable ·Checkmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.3.0:p27:*:*:*:*:*:* Versions 2.3.0 p27 Vulnerable ·Checkmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.3.0:p28:*:*:*:*:*:* Versions 2.3.0 p28 Vulnerable ·Checkmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.3.0:p29:*:*:*:*:*:* Versions 2.3.0 p29 Vulnerable ·Checkmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.3.0:p3:*:*:*:*:*:* Versions 2.3.0 p3 Vulnerable ·Checkmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.3.0:p30:*:*:*:*:*:* Versions 2.3.0 p30 Vulnerable ·Checkmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.3.0:p31:*:*:*:*:*:* Versions 2.3.0 p31 Vulnerable ·Checkmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.3.0:p32:*:*:*:*:*:* Versions 2.3.0 p32 Vulnerable ·Checkmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.3.0:p33:*:*:*:*:*:* Versions 2.3.0 p33 Vulnerable ·Checkmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.3.0:p34:*:*:*:*:*:* Versions 2.3.0 p34 Vulnerable ·Checkmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.3.0:p35:*:*:*:*:*:* Versions 2.3.0 p35 Vulnerable ·Checkmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.3.0:p36:*:*:*:*:*:* Versions 2.3.0 p36 Vulnerable ·Checkmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.3.0:p37:*:*:*:*:*:* Versions 2.3.0 p37 Vulnerable ·Checkmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.3.0:p38:*:*:*:*:*:* Versions 2.3.0 p38 Vulnerable ·Checkmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.3.0:p4:*:*:*:*:*:* Versions 2.3.0 p4 Vulnerable ·Checkmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.3.0:p5:*:*:*:*:*:* Versions 2.3.0 p5 Vulnerable ·Checkmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.3.0:p6:*:*:*:*:*:* Versions 2.3.0 p6 Vulnerable ·Checkmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.3.0:p7:*:*:*:*:*:* Versions 2.3.0 p7 Vulnerable ·Checkmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.3.0:p8:*:*:*:*:*:* Versions 2.3.0 p8 Vulnerable ·Checkmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.3.0:p9:*:*:*:*:*:* Versions 2.3.0 p9 Vulnerable ·Checkmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.4.0:-:*:*:*:*:*:* Versions 2.4.0 Vulnerable ·Checkmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.4.0:p1:*:*:*:*:*:* Versions 2.4.0 p1 Vulnerable ·Checkmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.4.0:p10:*:*:*:*:*:* Versions 2.4.0 p10 Vulnerable ·Checkmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.4.0:p11:*:*:*:*:*:* Versions 2.4.0 p11 Vulnerable ·Checkmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.4.0:p12:*:*:*:*:*:* Versions 2.4.0 p12 Vulnerable ·Checkmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.4.0:p13:*:*:*:*:*:* Versions 2.4.0 p13 Vulnerable ·Checkmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.4.0:p2:*:*:*:*:*:* Versions 2.4.0 p2 Vulnerable ·Checkmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.4.0:p3:*:*:*:*:*:* Versions 2.4.0 p3 Vulnerable ·Checkmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.4.0:p4:*:*:*:*:*:* Versions 2.4.0 p4 Vulnerable ·Checkmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.4.0:p5:*:*:*:*:*:* Versions 2.4.0 p5 Vulnerable ·Checkmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.4.0:p6:*:*:*:*:*:* Versions 2.4.0 p6 Vulnerable ·Checkmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.4.0:p7:*:*:*:*:*:* Versions 2.4.0 p7 Vulnerable ·Checkmk GmbH
  • cpe:2.3:a:checkmk:checkmk:2.4.0:p9:*:*:*:*:*:* Versions 2.4.0 p9 Vulnerable ·Checkmk GmbH

Remediation

  • Fix · CNA Checkmk (Checkmk GmbH) Fixed in 2.4.0p14, 2.3.0p39

Timeline

  1. 2026-10-02 Threatist record created from CVE-2025-39663
  2. 2026-10-03 Alias added: GHSA-m8fq-fxf8-wxx3

References

Exploit 2

Advisory 1

  • TI-2025-40190 Cross-site scripting in HTML logs of Synthetic Monitoring test services CVSS 4.0HIGH 7.3
  • TI-2024-19037 Brute-force protection ineffective for some login methods CVSS 3.1CRITICAL 9.8
  • TI-2024-05712 local IP restriction of internal HTTP endpoints CVSS 3.1CRITICAL 9.8
  • TI-2021-17818 The web management console of CheckMK Enterprise Edition (versions 1.5.0 to 2.0.0p9) does… CVSS 3.1HIGH 8.8
  • TI-2021-17817 The web management console of CheckMK Raw Edition (versions 1.5.0 to 1.6.0) allows a… CVSS 3.1HIGH 8.8
  • TI-2024-07982 Fix 2FA bypass via RestAPI CVSS 4.0CRITICAL 9.2
See all 107 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences