CVE-2026-8833 - Vulnerability Details - OpenCVE

Improper 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 versions allows an authenticated user to bypass URL validation and inject malicious URLs such as javascript: URIs, resulting in cross-site scripting when another user interacts with the crafted link.

Attack Vector Network

Attack Complexity Low

Privileges Required Low

Attack Requirements None

User Interaction Active

Vulnerable System Confidentiality Impact High

Vulnerable System Integrity Impact High

Vulnerable System Availability Impact High

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact Low

Subsequent System Availability Impact None

No CVSS v3.1

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Exploitation none

Automatable no

Technical Impact total

Vendors	Products
Checkmk	Checkmk

No data.

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References

Link	Providers
https://checkmk.com/werk/20002

History

Mon, 08 Jun 2026 13:30:00 +0000

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}`

Mon, 08 Jun 2026 13:00:00 +0000

Type	Values Removed	Values Added
Description		Improper 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 versions allows an authenticated user to bypass URL validation and inject malicious URLs such as javascript: URIs, resulting in cross-site scripting when another user interacts with the crafted link.
Title		XSS in urls
First Time appeared		Checkmk Checkmk checkmk
Weaknesses		CWE-79
CPEs		cpe:2.3:a:checkmk:checkmk:::::::: cpe:2.3:a:checkmk:checkmk:2.2.0:::::::*
Vendors & Products		Checkmk Checkmk checkmk
References		https://checkmk.com/werk/20002
Metrics		cvssV4_0 `{'score': 8.5, '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'}`

MITRE

Status: PUBLISHED

Assigner: Checkmk

Published: 2026-06-08T12:06:51.267Z

Updated: 2026-06-08T13:02:45.679Z

Reserved: 2026-05-18T14:06:43.958Z

Link: CVE-2026-8833

Vulnrichment

Updated: 2026-06-08T13:02:42.423Z

NVD

Status : Received

Published: 2026-06-08T13:16:33.900

Modified: 2026-06-08T13:16:33.900

Link: CVE-2026-8833

Redhat

No data.

OpenCVE Enrichment

No data.

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