Answer in brief
CVE-2026-100370 records a Medium severity (CVSS 4.7) vulnerability in DOMSanitizer - Incomplete data: URL Sanitization in DOMSanitizer::isDangerousUrl() Allows Base64-Encoded Payloads to Bypass href and xlink:href Validation. The current sources do not mark it as known exploited. The current feed maps rhukster/dom-sanitizer (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 4.7. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps rhukster/dom-sanitizer (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| rhukster/dom-sanitizergeneric | <1.0.15 | 1.0.15 |
Published upstream
Sep 28, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Sep 28, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Sep 28, 2026
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.
Quoted source text, attributed separately from HOL analysis.