What’s Vulnerable › Vulnerabilities

CVE-2026-8833: XSS in urls

• Severity: medium (CVSS 5.4 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.1% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-06-08 · updated 2026-10-23
• Weakness: CWE-79

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.

Affected products

• Checkmk GmbH Checkmk: 2.2.0, 2.2.0-b1, 2.2.0-b2, 2.2.0-b3, 2.2.0-b4, 2.2.0-b5 (+150)

References

• https://checkmk.com/werk/20002

Get alerted when CVE-2026-8833 or the next vulnerability affects your stack