---
id: CVE-2026-100370
title: DOMSanitizer is a DOM/SVG/MathML Sanitizer for PHP 7.3+
summary: >-
  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 …
severity: medium
cvss: 4.7
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:N/A:N'
cwe:
  - CWE-20
vendor: rhukster
product: dom-sanitizer
affected:
  - dom-sanitizer < 1.0.15
published: '2026-09-28'
updated: '2026-09-28'
sourceUpdated: '2026-09-28T21:17:10.280'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-100370'
references:
  - url: >-
      https://github.com/rhukster/dom-sanitizer/commit/10f97807e4501d60f63987f2e76a38cdbf312dcb
    label: security-advisories@github.com
  - url: >-
      https://github.com/rhukster/dom-sanitizer/commit/fb8f758b41134fc5fb2f563666f2330c69e31f94
    label: security-advisories@github.com
  - url: 'https://github.com/rhukster/dom-sanitizer/releases/tag/1.0.15'
    label: security-advisories@github.com
  - url: >-
      https://github.com/rhukster/dom-sanitizer/security/advisories/GHSA-wcj2-r6vg-rm97
    label: security-advisories@github.com
  - url: >-
      https://github.com/rhukster/dom-sanitizer/security/advisories/GHSA-wcj2-r6vg-rm97
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
tags:
  - nvd
  - cve.org
  - exploit-available
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-28T20:39:56.823996Z'
ingestedAt: '2026-09-28T21:20:54.774Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.