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CVE-2026-20915

HIGH CVSS 4.0: 8.5 EPSS 0.03%
Updated Apr 02, 2026
Checkmk
Parameter Value
CVSS 8.5 (HIGH)
Type CWE-79 (Cross-Site Scripting (XSS))
Vendor Checkmk
Public PoC No

Stored cross-site scripting (XSS) in Checkmk version 2.5.0 (beta) before 2.5.0b2 allows authenticated users with permission to create pending changes to inject malicious JavaScript into the Pending Changes sidebar, which will execute in the browsers of other users viewing the sidebar.

Attack Parameters

Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Attack Requirements
None
No additional conditions
Privileges Required
High
Admin privileges needed
User Interaction
Passive
Minimal interaction

Impact Assessment

Confidentiality
High
Complete data leak
Integrity
High
Complete data modification
Availability
High
Complete denial of service

CVSS Vector v4.0

Vulnerable Products 1

Configuration From (including) Up to (excluding)
Checkmk Checkmk
cpe:2.3:a:checkmk:checkmk:2.5.0:b1:*:*:*:*:*:*