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CVE-2025-39663

27
FAUCET Score

CVE-2025-39663 is a high-severity Cross-Site Scripting (XSS) vulnerability affecting Checkmk versions before 2.4.0p14, 2.3.0p39, 2.2.0, and 2.1.0 (EOL). This flaw allows a compromised remote Checkmk site to inject malicious HTML into service outputs displayed on a central monitoring site. With a CVSS score of 8.4 (HIGH), successful exploitation could lead to high impact on confidentiality, integrity, and availability, requiring high privileges and user interaction. Currently, there is no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion surrounding this vulnerability.

Impacted Technologies

VendorProductVersion(s)CPE
>= 2.0.0, < 2.3.0CPE matchmatch criteria
cpe:2.3:a:checkmk:checkmk:*:*:*:*:*:*:*:*
2.3.0CPE matchmatch criteria
cpe:2.3:a:checkmk:checkmk:2.3.0:-:*:*:*:*:*:*
2.3.0CPE matchmatch criteria
cpe:2.3:a:checkmk:checkmk:2.3.0:p1:*:*:*:*:*:*
2.3.0CPE matchmatch criteria
cpe:2.3:a:checkmk:checkmk:2.3.0:p10:*:*:*:*:*:*
2.3.0CPE matchmatch criteria
cpe:2.3:a:checkmk:checkmk:2.3.0:p11:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 4.0

8.5HIGH

CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
HIGH
User Interaction
PASSIVE
VS Confidentiality
HIGH
VS Integrity
HIGH
VS Availability
HIGH
SS Confidentiality
NONE
SS Integrity
NONE
SS Availability
NONE
Exploit Maturity
NOT_DEFINED
CvssVersion
4.0

Exploit Intelligence

EPSS Score
0.56%
Probability of exploitation in next 30 days
EPSS Percentile
43.4%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0056 is in the 55th percentile among its peer group of 147 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.4 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.2 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Remediation records are not available for this CVE.

References

seclists.org / fulldisclosure/2025/Nov/0
ExploitMailing ListThird Party Advisory
checkmk.com / werk/17998
Vendor Advisory
github.com / sbaresearch/advisories/tree/82fd27e4570433464c30b35150b197db9a850f4e/2025/SBA-ADV-20250729-01_Checkmk_Cross_Site_Scripting
ExploitThird Party Advisory