Vulnerability in DOMSanitizer is a DOM/SVG/MathML Sanitizer for PHP (CVE-2026-100370)
Summary
Vulnerability in DOMSanitizer is a DOM/SVG/MathML Sanitizer for PHP (CVE-2026-100370). Risk of unauthorized operations or information disclosure.
Original description
The description as published by the source.
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 (, 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.
Source: NIST National Vulnerability Database NVD
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-100370 has been found in DOMSanitizer is a DOM/SVG/MathML Sanitizer for PHP.
Risk of unauthorized operations or information disclosure. CVSS score: 4.7/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "DOMSanitizer is a DOM/SVG/MathML Sanitizer for PHP CVE-2026-100370" on the vendor's site.
CVE-2026-100370 (DOMSanitizer is a DOM/SVG/MathML Sanitizer for PHP) — CWE-20 / CVSS v3 4.7
Attack vector: remote (network-reachable) / unauthenticated
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-20) exists in DOMSanitizer is a DOM/SVG/MathML Sanitizer for PHP.
Check the vendor advisory for the affected versions of DOMSanitizer is a DOM/SVG/MathML Sanitizer for PHP.
Severity: Medium (CVSS 4.7/10). Risk of unauthorized operations or information disclosure.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで DOMSanitizer is a DOM/SVG/MathML Sanitizer for PHP を使っているサービスとバージョンを洗い出す。
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2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。