CVE-2026-8078Network attack vector

Stored XSS via unescaped changelog values

Published Jun 8, 2026 · Updated Jun 8, 2026

Stored XSS in Checkmk's global settings change log allows remote authenticated users to execute script in other users' browsers. The global-settings workflow embeds attacker-controlled new values in change-log messages without HTML escaping, and the Activate Changes and Audit log views render the stored markup. By default, administrator permission to change global settings is required; viewing either affected page triggers the script in another user's browser, enabling page-content modification or browser actions in that user's session.

CVSS severity4.8
Medium
EPSS probability0.14%
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's global settings change log allows remote authenticated users to execute script in other users' browsers. The global-settings workflow embeds attacker-controlled new values in change-log messages without HTML escaping, and the Activate Changes and Audit log views render the stored markup. By default, administrator permission to change global settings is required; viewing either affected page triggers the script in another user's browser, enabling page-content modification or browser actions in that user's session.

The record

CVE
CVE-2026-8078
Published
Jun 8, 2026
Updated
Jun 8, 2026
Vendor
Checkmk GmbH
Product
Checkmk
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Jun 8, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 8, 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 <2.3.0p48
  3. Affected versionversion=2.4.0 <2.4.0p31
  4. Affected versionversion=2.5.0 <2.5.0p5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

Checkmk GmbH · Checkmkversion=2.2.0; version=2.3.0 <2.3.0p48; version=2.4.0 <2.4.0p31; version=2.5.0 <2.5.0p5

Published CVSS scores

4.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N
4.8Checkmk GmbHCVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:N/VI:L/VA:N/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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1059.007Command and Scripting Interpreter: JavaScript/JScript

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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