CVE-2025-39663: checkmk gmbh checkmk
CVSS: 8.5v4.0HighAnalyzed
AliasesUBUNTU-CVE-2025-39663
Published 30-10-2025Last modified 07-11-2025
Vulnerability summary
CVE-2025-39663 is a high (CVSS 8.5) vulnerability in checkmk gmbh checkmk. EPSS estimates a 0.60% chance of exploitation in the next 30 days, higher than 47.9% of scored vulnerabilities. 2 public exploits are recorded.
CVSS score
8.5/10
010
High · v4.0 (CVE.org)EPSS score
0.60%
0%100%
Low · +0.04 pp in 30 daysKEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits2github, reference
Timeline
- 30-10-2025PublishedVulnerability first disclosed.
- 07-11-2025Last modifiedVulnerability information updated.
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).
CVSS metrics
5 scores · 3 sources · 2 versionsHigh 8.5Preferred score · CVE.org (CNA)
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:NSourcesAll 3 agree
- OSV · UbuntuEcosystem advisory · calculated8.5HighCVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- NVDNIST8.5HighCVSS: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
High 8.4Preferred score · OSV · Ubuntu (Ecosystem advisory) · calculated from vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:HSourcesAll 2 agree
- NVDNIST8.4HighCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:H
EPSS trend
Probability
0.60%
Chance of exploitation in the next 30 days
Percentile
48%
Versus all other CVEs
30-day change
+0.04 pp
From 0.56% on 20-09-2026
20-09-202620-10-2026
EPSS score0.60%
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
2 foundAdvisories
Maturity: poc
Exploit Reference (seclists.org)
Maturity: unknown
Weaknesses
CWE · root cause- CWE-80Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes special characters such as "<", ">", and "&" that could be interpreted as web-scripting elements when they are sent to a downstream component that processes web pages.
- CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.
Affected systems
Checkmk1 product
- checkmk≥ 2.0.0, < 2.3.0 | 2.3.0 | 2.3.0:p1 | 2.3.0:p10 | 2.3.0:p11 | 2.3.0:p12 | 2.3.0:p13 | 2.3.0:p14 | 2.3.0:p15 | 2.3.0:p16 | 2.3.0:p17 | 2.3.0:p18 | 2.3.0:p19 | 2.3.0:p2 | 2.3.0:p20 | 2.3.0:p21 | 2.3.0:p22 | 2.3.0:p23 | 2.3.0:p24 | 2.3.0:p25 | 2.3.0:p26 | 2.3.0:p27 | 2.3.0:p28 | 2.3.0:p29 | 2.3.0:p3 | 2.3.0:p30 | 2.3.0:p31 | 2.3.0:p32 | 2.3.0:p33 | 2.3.0:p34 | 2.3.0:p35 | 2.3.0:p36 | 2.3.0:p37 | 2.3.0:p38 | 2.3.0:p4 | 2.3.0:p5 | 2.3.0:p6 | 2.3.0:p7 | 2.3.0:p8 | 2.3.0:p9 | 2.4.0 | 2.4.0:p1 | 2.4.0:p10 | 2.4.0:p11 | 2.4.0:p12 | 2.4.0:p13 | 2.4.0:p2 | 2.4.0:p3 | 2.4.0:p4 | 2.4.0:p5 | 2.4.0:p6 | 2.4.0:p7 | 2.4.0:p9
Checkmk gmbh1 product
- checkmkEOL≥ 2.4.0, < 2.4.0p14 | ≥ 2.3.0, < 2.3.0p39 | 2.2.0 | 2.1.0
Ubuntu1 product
- check-mkAll versions (No fix recorded)
3 vendors · 3 products