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Werk #19033: Cross-site scripting in dashlet title

Component Setup
Title Cross-site scripting in dashlet title
Date Mar 3, 2026
Level Trivial Change
Class Security Fix
Compatibility Compatible - no manual interaction needed
Checkmk versions & editions
2.6.0b1
Not yet released
Checkmk Community, Checkmk Pro, Checkmk Ultimate, Checkmk Ultimate MT
2.5.0b3
Not yet released
Checkmk Community, Checkmk Pro, Checkmk Ultimate, Checkmk Ultimate MT
2.4.0p25 Checkmk Community, Checkmk Pro, Checkmk Ultimate, Checkmk Ultimate MT
2.3.0p46 Checkmk Community, Checkmk Pro, Checkmk Ultimate, Checkmk Ultimate MT

Insufficient sanitization allowed stored XSS attacks in the title links of dashboard dashlets when a user clicked the title of a dashlet on an attacker-controlled dashboard. In order to exploit the issue, the attacker needed to be able to create and share a dashboard with the victim (e.g. by making it public), and the victim would need to click on the link.

Links are now sanitized appropriately to disallow running Javascript code. Note that it is still possible to make title links point to arbitrary websites.

We thank Alex Williams (Pellera Technologies) for reporting this issue.

Who's Affected:

This issue affect all editions of Checkmk in the default configuration.

Affected Versions:

  • 2.4.0
  • 2.3.0
  • 2.2.0 (EOL)

Mitigations:

Avoid clicking dashboard title links on untrusted dashboards.

Vulnerability Management:

We have rated the issue with a CVSS Score of 8.5 High (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) and assigned CVE-2026-3466.

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