VDB-330571 · CVE-2025-39663 · Nessus 272186

Checkmk up to 2.1.0/2.2.0/2.3.0p38/2.4.0p13 cross site scripting

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
5.3	$0-$5k	0.00

Summaryinfo

A vulnerability has been found in Checkmk up to 2.1.0/2.2.0/2.3.0p38/2.4.0p13 and classified as problematic. Affected is an unknown function. This manipulation causes cross site scripting. This vulnerability is handled as CVE-2025-39663. The attack can be initiated remotely. There is not any exploit available. The affected component should be upgraded.

Detailsinfo

A vulnerability classified as problematic was found in Checkmk up to 2.1.0/2.2.0/2.3.0p38/2.4.0p13. Affected by this vulnerability is an unknown part. The manipulation with an unknown input leads to a cross site scripting vulnerability. The CWE definition for the vulnerability is CWE-80. 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. As an impact it is known to affect integrity. The summary by CVE is:

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).

It is possible to read the advisory at checkmk.com. This vulnerability is known as CVE-2025-39663 since 04/16/2025. The exploitation appears to be easy. The attack can be launched remotely. The exploitation needs additional levels of successful authentication. It demands that the victim is doing some kind of user interaction. The technical details are unknown and an exploit is not publicly available. The attack technique deployed by this issue is T1059.007 according to MITRE ATT&CK.

The vulnerability scanner Nessus provides a plugin with the ID 272186 (Linux Distros Unpatched Vulnerability : CVE-2025-39663), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 2.3.0p39 or 2.4.0p14 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (272186). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Name

Checkmk

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 5.4
VulDB Meta Temp Score: 5.3

VulDB Base Score: 2.4
VulDB Temp Score: 2.3
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 8.4
NVD Vector: 🔒

CVSSv2info

AV	AC	Au	C	I	A
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Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Cross site scripting
CWE: CWE-80 / CWE-74 / CWE-707
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Nessus ID: 272186
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2025-39663

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Checkmk 2.3.0p39/2.4.0p14

Timelineinfo

04/16/2025 CVE reserved
10/30/2025 +197 days Advisory disclosed
10/30/2025 +0 days VulDB entry created
12/04/2025 +35 days VulDB entry last update

Sourcesinfo

Advisory: checkmk.com
Status: Confirmed

CVE: CVE-2025-39663 (🔒)
GCVE (CVE): GCVE-0-2025-39663
GCVE (VulDB): GCVE-100-330571

Entryinfo

Created: 10/30/2025 14:35
Updated: 12/04/2025 03:27
Changes: 10/30/2025 14:35 (65), 11/03/2025 20:38 (2), 12/04/2025 03:27 (11)
Complete: 🔍
Cache ID: 216::103

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.