CVE-2026-33276 XSS in Unified Search via Unescaped Host/Service Names
Authenticated users can inject JavaScript via host names, executing code in other users' browsers during Unified Search.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-33276?
CVE-2026-33276 is a high-severity cross-site scripting vulnerability in Checkmk Checkmk, published on 31 Mar 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official description
Stored cross-site scripting (XSS) in Checkmk 2.5.0 (beta) before 2.5.0b2 allows authenticated users with permission to create hosts or services to execute arbitrary JavaScript in the browsers of other users performing searches in the Unified Search feature.
Weakness: CWE-79
Which versions are affected by CVE-2026-33276?
It affects 1 product.
Products include Checkmk Checkmk.
How do I fix CVE-2026-33276?
No fix has been published for CVE-2026-33276 yet. Limit exposure of the affected software until one is available.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-33276 being exploited?
There is no known exploitation of CVE-2026-33276 in the wild and no public exploit code.
Other vulnerabilities in Checkmk Checkmk
- CVE-2025-39666 omd: Local privilege escalation when executing omd commands as root
- CVE-2024-8606 Fix 2FA bypass via RestAPI
- CVE-2022-46836 PHP code injection in watolib
- CVE-2025-32919 Privilege Escalation in Windows License plugin for Checkmk Windows Agent
- CVE-2024-28827 Privilege escalation in Windows agent
Sources
Also known as GHSA-h3c2-xwq9-6ph4, UBUNTU-CVE-2026-33276.