CVE-2026-20915: Stored cross-site scripting in Pending Changes sidebar

Published Mar 31, 2026
·
Updated

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.

Affected Software

2 affected components
Tribe29 Checkmk<2.5.0b2
Checkmk Checkmk=2.5.0-b1

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade Checkmk to a version that resolves this vulnerability.

    Fixed in 2.5.0b2

Event History

Mar 31, 2026
CVE Published
via MITRE·01:51 PM
Data Sourced
via MITRE·01:51 PM
DescriptionWeakness
Data Sourced
via NVD·03:16 PM
DescriptionSeverityWeaknessAffected Software

Frequently Asked Questions

1

What is the severity of CVE-2026-20915?

CVE-2026-20915 is classified as a medium severity vulnerability due to its potential for exploitation by authenticated users.

2

How do I fix CVE-2026-20915?

To fix CVE-2026-20915, update Checkmk to version 2.5.0b2 or later, which addresses the stored XSS issue.

3

Who is affected by CVE-2026-20915?

Users of Checkmk version 2.5.0 (beta) before 2.5.0b2 are affected by CVE-2026-20915 if they have the permission to create pending changes.

4

What type of vulnerability is CVE-2026-20915?

CVE-2026-20915 is a stored cross-site scripting (XSS) vulnerability.

5

What can an attacker do with CVE-2026-20915?

An attacker with the necessary permissions can inject malicious JavaScript that executes in the browsers of users viewing the Pending Changes sidebar.

Contact

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