CVE-2026-3466Network attack vector

Stored XSS via unsanitized dashlet title links

Published Apr 7, 2026 · Updated Apr 7, 2026

Stored XSS in Checkmk 2.2.0, 2.3.0 before 2.3.0p46, 2.4.0 before 2.4.0p25, and 2.5.0 beta before 2.5.0 allows attackers to run JavaScript. The dashboard renderer failed to sanitize attacker-controlled title-link URLs, leaving JavaScript URLs executable when a shared dashlet or widget title was clicked. Dashboard creation and sharing privileges plus a victim click are required, and all editions are affected in the default configuration.

CVSS severity8.5
High
EPSS probability0.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in Checkmk 2.2.0, 2.3.0 before 2.3.0p46, 2.4.0 before 2.4.0p25, and 2.5.0 beta before 2.5.0 allows attackers to run JavaScript. The dashboard renderer failed to sanitize attacker-controlled title-link URLs, leaving JavaScript URLs executable when a shared dashlet or widget title was clicked. Dashboard creation and sharing privileges plus a victim click are required, and all editions are affected in the default configuration.

The record

CVE
CVE-2026-3466
Published
Apr 7, 2026
Updated
Apr 7, 2026
Vendor
Checkmk GmbH
Product
Checkmk
Classifications
CWE-79, T1566.002
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 7, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 7, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=2.2.0
  2. Affected versionversion=2.3.0 <2.3.0p46
  3. Affected versionversion=2.4.0 <2.4.0p25
  4. Affected versionversion=2.5.0b1 <2.5.0b3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Checkmk GmbH · Checkmkversion=2.2.0; version=2.3.0 <2.3.0p46; version=2.4.0 <2.4.0p25; version=2.5.0b1 <2.5.0b3

Published CVSS scores

5.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
8.5Checkmk GmbHCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:H/VI:H/VA:H/SC:N/SI:L/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1566.002Spearphishing Link

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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