CVE-2025-39663

Exploitation

Public exploit code exists. CISA's assessment records a public proof of concept. That is not a report of exploitation in the wild.

SSVC decision

• ExploitationpocPublic proof-of-concept exploit code exists. Not a report of exploitation in the wild.
• AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
• Technical ImpacttotalSuccessful exploitation gives total control of the vulnerable component.

CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.

EPSS probability

0.60% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 48.5% of scored records. A rank, not a probability.

NVD base score

8.5 (CVSS v4.0), scored by the NVD independently of the CNA.

NVD CVSS vector

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

NVD analysis status

Analyzed. NVD last modified this record on 2026-10-19.

Red Hat severity

No Red Hat rating. Red Hat rates the CVEs that affect its products.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

Published

2025-10-30 10:43Z12 MO AGO

Last updated

2025-11-07 16:04Z11 MO AGO

Reserved

2025-04-16

Assigning CNA

Checkmk

Record state

PUBLISHED

Severity

High (CVSS 8.5)

CNA CVSS vector

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

Weaknesses

• CWE-80Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)Variant
• CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')Base

Data version

5.2

Document digest

6d0cf5932c74b3255f3dacbf4a4ecbdd9b1f2288ae8cab42d09670ee5ff7a203

• checkmk.comhttps://checkmk.com/werk/17998
• github.comhttps://github.com/sbaresearch/advisories/tree/82fd27e4570433464c30b35150b197db9a850f4e/2025/SBA-ADV-20250729-01_Checkmk_Cross_Site_Scripting
• seclists.orghttp://seclists.org/fulldisclosure/2025/Nov/0