CVE-2026-20915 PUBLISHED

Stored cross-site scripting in Pending Changes sidebar

Assigner: Checkmk
Reserved: 23.03.2026 Published: 31.03.2026 Updated: 31.03.2026

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.

Metrics

CVSS 4.0

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:H/VI:H/VA:H/SC:N/SI:L/SA:N
CVSS Score: 8.5

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	High	Confidentiality	None
Attack Complexity	Low	Integrity	High	Integrity	Low
Attack Requirements	None	Availability	High	Availability	None
Privileges Required	High
User Interaction	Passive

CVSS 4.0

Product Status

Vendor	Checkmk GmbH
Product	Checkmk
Versions	Default: unaffected affected from 2.5.0b1 to 2.5.0b2 (excl.)

References

https://checkmk.com/werk/19526

Problem Types

CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') CWE

Impacts

CAPEC-592: Stored XSS