CVE-2026-100370: Rhukster Dom-Sanitizer

Medium severity, CVSS 4.7. EPSS: 0.3% chance of exploitation in the next 30 days.

DOMSanitizer is a DOM/SVG/MathML Sanitizer for PHP 7.3+. Prior to version 1.0.15, the isDangerousUrl() method is responsible for rejecting dangerous URL values in the href and xlink:href attributes. The weakness is that "javascript:" is rejected as a scheme, while "data:" is rejected only when the literal substring onload appears in the URL value (/^data:.*onload/i). Because data: payloads are routinely Base64-encoded, the dangerous content (<script>, event handlers, etc.) is invisible to that substring test. A URL such as data:text/html;base64,… therefore survives in href / xlink:href, even though the decoded payload is active markup. This is an incomplete input-validation / sanitization defect in the sanitizer itself. This issue has been patched in version 1.0.15.

Affected products

• Rhukster Dom-Sanitizer: before 1.0.15 (fixed in 1.0.15)

Published 2026-09-28. Last modified 2026-09-30.