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NVD / CVE Program· CNA Checkmk

CVE-2026-3466: Cross-site scripting in dashlet title

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: 0.22% (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 2.3.0p46, 2.4.0p25, 2.5.0.

Low priority for now. Upgrade to Checkmk GmbH Checkmk 2.3.0p46, 2.4.0p25, 2.5.0 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

Insufficient sanitization of dashboard dashlet title links in Checkmk 2.2.0 (EOL), Checkmk 2.3.0 before 2.3.0p46, Checkmk 2.4.0 before 2.4.0p25, and Checkmk 2.5.0 (beta) before 2.5.0 allows an attacker with dashboard creation privileges to perform stored cross-site scripting (XSS) attacks by tricking a victim into clicking a crafted dashlet title link on a shared dashboard.

HighCVSS 8.5 · v4.0—No exploit Fix available
Published
Apr 7, 2026
Updated
Jun 17, 2026
EPSS
0.2% · 13th percentile

Report tools

JSON

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.

Follow CVE-2026-3466

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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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.

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Affected 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.

VendorProduct
checkmkcheckmk

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 headers

Affected 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
    • 2.3.0 and later · before 2.3.0p46affected · semver
    • 2.4.0 and later · before 2.4.0p25affected · semver
    • 2.5.0b1 and later · before 2.5.0affected · semver

Same product

checkmk: all records

Other highest-scoring records for the same primary product.

  • CVE-2024-28825Brute-force protection ineffective for some login methods
    39Monitor
  • CVE-2022-48317Insecure Termination of RestAPI Session Tokens
    39Monitor
  • CVE-2025-39666omd: Local privilege escalation when executing omd commands as root
    37Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2026-33276Mar 31, 2026 · XSS in Unified Search via Unescaped Host/Service Names
    34Monitor
  • ← EarlierCVE-2026-24096Apr 1, 2026 · Insufficient permission validation on multiple REST API Quick Setup endpoints
    21Monitor
  • Later →CVE-2026-33455Apr 10, 2026 · Livestatus injection in monitoring quicksearch
    21Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Checkmk GmbH Checkmk2.3.0p46Vendor (CNA)
Checkmk GmbH Checkmk2.4.0p25Vendor (CNA)
Checkmk GmbH Checkmk2.5.0Vendor (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.

No history yet (it accumulates with the daily EPSS job).

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 researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-209157 days apartStored cross-site scripting in Pending Changes sidebar
    34Monitor
  • CVE-2026-332767 days apartXSS in Unified Search via Unescaped Host/Service Names
    34Monitor
  • CVE-2026-718662 days apartFix stored XSS in URL dashboard widget via dangerous URI schemes
    34Monitor
  • CVE-2026-883362 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 v
    34Monitor
  • CVE-2025-6499940 days apartCross-site scripting in HTML logs of Synthetic Monitoring test services
    29Monitor
  • CVE-2026-954962 days apartFix XSS in service discovery active check output
    19Monitor

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 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

ts
commentEl.innerHTML = comment.body;

Fixed

ts
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.

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (2 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records