Fix stored XSS in URL dashboard widget via dangerous URI schemes
Noroxi assessment
Priority: Monitor (action score 34/100)
- The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
- Probability of exploitation in the next 30 days: 0.23% (FIRST EPSS).
- Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No special conditions are required; it is repeatable.
- Fixed version: Checkmk GmbH Checkmk 2.3.0p48, 2.4.0p31, 2.5.0p5.
Low priority for now. Upgrade to Checkmk GmbH Checkmk 2.3.0p48, 2.4.0p31, 2.5.0p5 or later.
Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it
Primary sources: NVD · CVE.org · FIRST EPSS
Stored cross-site scripting in the URL dashboard widget in Checkmk <2.5.0p5, <2.4.0p31, <2.3.0p48, and all 2.2.0 versions allows a user with dashboard editing permissions to store a URL with a dangerous URI scheme such as javascript: that executes scripts in other users' browsers when they view the dashboard.
- Published
- Jun 8, 2026
- Updated
- Oct 6, 2026
- EPSS
- 0.2% · 13th percentile
- CWE
- CWE-79
Report tools
Action score
34
Monitor
Low priority for now.
- CVSS
- 34 / 40 · 8.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.2%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- total
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · Checkmk
- 8.5
- NVD has not scored this yet; the score shown is the CNA’s.
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
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Get told when this record changes
- Not in KEV: no record of exploitation in the wild
- No public exploit code on record
- A fix has been released
If any of these changes, we'll tell you in the daily email digest.
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Noroxi analysis
What does it mean in your environment?
The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.
We use this product, ask for helpAffected systems
Is your version affected?
Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.
| Vendor | Product | CPE |
|---|---|---|
| checkmk | checkmk | cpe:2.3:a:checkmk:checkmk |
Limit the impact of XSS
This is a cross-site scripting (XSS) vulnerability. A well-configured Content-Security-Policy doesn't fix it, but greatly reduces its impact. Check your site's CSP and other security headers for free.
Check security headersAffected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- checkmk checkmk2.2.0
- checkmk checkmk2.3.0
- checkmk checkmk2.4.0
- checkmk checkmk2.5.0
Versions reported by the vendor
Affected version ranges reported by the assigning authority (Checkmk). Independent of NVD's CPE analysis and usually ahead of it.
Checkmk GmbH Checkmk
- 2.2.0affected
- 2.5.0 and later · before 2.5.0p5affected · semver
- 2.4.0 and later · before 2.4.0p31affected · semver
- 2.3.0 and later · before 2.3.0p48affected · semver
Same product
checkmk: all recordsOther highest-scoring records for the same primary product.
- CVE-2024-28825Brute-force protection ineffective for some login methods39Monitor
- CVE-2022-48317Insecure Termination of RestAPI Session Tokens39Monitor
- CVE-2025-39666omd: Local privilege escalation when executing omd commands as root37Monitor
Published before and after this one in the same product
- ← EarlierCVE-2026-33457Apr 10, 2026 · Potential livestatus injection in prediction graph page21Monitor
- ← EarlierCVE-2024-47091May 13, 2026 · Privilege escalation via mk_mysql agent plugin on Windows20Monitor
- Later →CVE-2026-7765Jun 8, 2026 · User Messages widget leaked issuer messages on shared dashboards25Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| Checkmk GmbH Checkmk | 2.3.0p48 | Vendor (CNA) |
| Checkmk GmbH Checkmk | 2.4.0p31 | Vendor (CNA) |
| Checkmk GmbH Checkmk | 2.5.0p5 | Vendor (CNA) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
- CVE-2026-88330 days apartImproper neutralization of HTML-encoded characters in the URL validation function in Checkmk <2.5.0p5, <2.4.0p31, <2.3.0p48, and all 2.2.0 v34Monitor
- CVE-2026-346662 days apartCross-site scripting in dashlet title34Monitor
- CVE-2026-2091569 days apartStored cross-site scripting in Pending Changes sidebar34Monitor
- CVE-2026-3327669 days apartXSS in Unified Search via Unescaped Host/Service Names34Monitor
- CVE-2025-64999102 days apartCross-site scripting in HTML logs of Synthetic Monitoring test services29Monitor
- CVE-2026-95490 days apartFix XSS in service discovery active check output19Monitor
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- A low-privileged account is enough.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- Integrity
- Availability
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- A
- Scope
- X
Weakness class (CWE)
CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')CVSS vector
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
nvd-secondary
Root cause
User content is inserted into the page as HTML. The browser interprets the content as code rather than data.
The bug in code
The whole CWE-79 classA representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.
Vulnerable
commentEl.innerHTML = comment.body;Fixed
commentEl.textContent = comment.body;Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
ATT&CK techniques
—
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Vendor advisories and official records. Exploit/PoC links are deliberately left out.