CVE-2026-33276
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedStored 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.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceStored XSS vulnerability in Checkmk 2.5.0 (beta) before 2.5.0b2 allows authenticated users with host/service creation permissions to inject malicious JavaScript into the Unified Search feature, which then executes in the browsers of other users when they perform searches.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data= 2.5.0CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- Low
- User interaction
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify the installed Checkmk versionRun 'cmk --version' or check the Checkmk web interface under 'User > About Checkmk' to confirm the exact version numberAffected if The version is exactly 2.5.0 (the beta release)
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Verify if host creation permissions existNavigate to 'Users > Roles and Permissions' in the Checkmk web interface and review which roles have 'Hosts' or 'Service' creation permissions enabledAffected if Any role has host or service creation permissions enabled for untrusted users
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Inspect host names for malicious payloadsGo to 'Setup > Hosts' and review all host names for suspicious patterns such as <script>, javascript:, onload, onerror, or other HTML/JavaScript tagsAffected if Any host name contains XSS payload patterns
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Inspect service descriptions for malicious payloadsGo to 'Setup > Services' and review service descriptions for suspicious patterns including script tags, event handlers, or encoded payloadsAffected if Any service description contains XSS payload patterns
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Review Unified Search history for executed payloadsCheck browser developer console or Checkmk logs for any XSS errors or unexpected JavaScript execution when using the Unified Search boxAffected if XSS errors appear in console or logs after searching host/service terms
You are affected if running Checkmk version 2.5.0 and your environment has users with host/service creation permissions who may have injected or could inject malicious scripts into host or service fields that execute via Unified Search.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scopedUpgrade Checkmk to version 2.5.0b2 or later. Until then, restrict the host/service creation permission to only trusted users and monitor for suspicious activity in the Unified Search feature.
Checkmk 2.5.0b2 or later
- Upgrade Checkmk from version 2.5.0 (beta) to version 2.5.0b2 or later
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,960.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-33276 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-33276 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data