CVE-2025-39663

Cross Site Scripting through compromised remote site

HIGH
8.4
CVSS Score
Published: October 30, 2025 at 10:43 AM UTC
Updated: October 19, 2026 at 01:10 PM UTC
1 product affected across 1 vendorCheckmk

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Severity
HIGH8.4
Exploit prediction
EPSS 0.6%
SSVC
PoC

Description

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).

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

References (3)

Vendor Advisory
Source: cverecord
https://checkmk.com/werk/17998
ExploitMailing ListThird Party Advisory
Source: af854a3a-2127-422b-91ae-364da2661108
http://seclists.org/fulldisclosure/2025/Nov/0

SSVC — Action Prioritization

SSVCPoCNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
HIGH
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-80CWE-79

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