EUVD-2026-35053
GHSA-hc7p-6r8x-vr4q
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A05:2025 - Injection
ASVS 5.0
V1 - Encoding and Sanitization Output encoding, context-aware escaping
MITRE ATT&CK
2 techniques across 2 tactics: Initial Access, Execution The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
Get an e-mail when this CVE is exploited, patched or re-scored. Free account.
Alert meAnalysisAIv1 – Jun 08, 2026
Stored/reflected cross-site scripting in Checkmk monitoring platform versions prior to 2.5.0p5, 2.4.0p31, 2.3.0p48, and all 2.2.0 releases allows authenticated users to bypass URL validation by leveraging HTML-encoded characters, enabling injection of javascript: URIs that execute in another user's browser session. The CVSS 4.0 score of 8.5 reflects the high impact on confidentiality, integrity, and availability when a victim interacts with a crafted link, though no public exploit identified at time of analysis and the issue requires both low-privilege authentication and user interaction.
Affected VersionsENISA
Affected Packages
Source: OSV (Open Source Vulnerabilities)
Affects your stack
Affects 1 package in euvd
Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Know when Checkmk gets its next vulnerability
- Watch products and get an email when something new is published
- Check this CVE against your own stack and servers
- Exploit and PoC references, threat intelligence from 22 sources
No credit card · 7-day full trial
Severity by source
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:H/VI:H/VA:H/SC:N/SI:L/SA:N
Primary rating from Vendor (Checkmk) · only source for this CVE.
CVSS VectorVendor: Checkmk
Lifecycle Timeline
2DescriptionCVE.org
Improper neutralization of HTML-encoded characters in the URL validation function in Checkmk <2.5.0p5, <2.4.0p31, <2.3.0p48, and all 2.2.0 versions allows an authenticated user to bypass URL validation and inject malicious URLs such as javascript: URIs, resulting in cross-site scripting when another user interacts with the crafted link.
Executive ViewAI
Checkmk monitoring platform versions before 2.5.0p5, 2.4.0p31, and 2.3.0p48 allow authenticated users to inject malicious scripts into monitoring interfaces, creating risk of administrator account compromise and data breach. Organizations using vulnerable versions face potential loss of infrastructure visibility and unauthorized access to sensitive operational monitoring. Immediate patching is required to prevent exploitation.
Within 24 hours: inventory all Checkmk deployments and identify current versions. Within 7 days: apply patches to Checkmk 2.5.0p5 (or newer 2.5.x), 2.4.0p31 (or newer 2.4.x), and 2.3.0p48 (or newer 2.3.x). Within 30 days: evaluate any Checkmk 2.2.0 instances and execute migration plan to supported, patched versions.
Apply vendor patch. Interim: restrict Checkmk access to internal networks; disable external link sharing; monitor authentication logs for suspicious activity; educate administrators on XSS risk in monitoring interfaces.
Threat Intelligence Overview
NVD
CVE.org
EPSS
Vulnrichment
VulDB
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Cross-Site Scripting occurs when an application accepts untrusted data and sends it to a web browser without proper validation or encoding.
Check_MK before 1.2.8p26 mishandles certain errors within the failed-login save feature because of a race condition, whi
The web management console of CheckMK Raw Edition (versions 1.5.0 to 1.6.0) allows a misconfiguration of the web-app Dok
The web management console of CheckMK Enterprise Edition (versions 1.5.0 to 2.0.0p9) does not properly sanitise the uplo
Local privilege escalation in the Checkmk Windows Agent's Windows License plugin allows an authenticated low-privileged
Stored/transmitted cross-site scripting in Checkmk's distributed monitoring lets an attacker who already controls a remo
Authenticated path traversal in Checkmk's report scheduler lets a user with valid application credentials write report f
Improper restriction of excessive authentication attempts on some authentication methods in Checkmk before 2.3.0b5 (beta
The CheckMK management web console (versions 1.5.0 to 2.0.0) does not sanitise user input in various parameters of the W
Local privilege escalation in Checkmk allows site users with high privileges to escalate to root by manipulating site co
Bypass of two factor authentication in RestAPI in Checkmk < 2.3.0p16 and < 2.2.0p34 allows authenticated users to bypass
Improper neutralization of active check command arguments in Checkmk < 2.1.0p32, < 2.0.0p38, < 2.2.0p4 leads to arbitrar
Improper neutralization of livestatus command delimiters in the RestAPI in Checkmk < 2.0.0p36, < 2.1.0p28, and < 2.2.0b8
Exploit-DB