Bug 2556338 (CVE-2026-113657)

Summary: CVE-2026-113657 sanitize-html: sanitize-html: arbitrary script execution via namespace-prefixed SVG animation elements
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
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Priority: low    
Version: unspecifiedKeywords: Security
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OS: Linux   
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A flaw was found in sanitize-html. This vulnerability allows a remote attacker to achieve arbitrary script execution when an application is configured to permit namespace-prefixed Scalable Vector Graphics (SVG) animation elements. By submitting specially crafted SVG markup, an attacker can bypass URL validation checks and rewrite link destinations to unsafe addresses. When a user activates the affected link, malicious script executes within their browser session.
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Description OSIDB Bzimport 2026-10-20 17:02:16 UTC 
ApostropheCMS is an open-source Node.js content management system, and sanitize-html provides a simple HTML sanitizer with a clear API. From sanitize-html 2.17.7 until 2.18.0, an application configuration that permits namespace-prefixed SVG animation elements and the relevant URL-targeting attributes can bypass the SMIL URL protection because prefixed tag names do not match the unprefixed animation-element check. The bypass can rewrite a link destination to an unsafe URI after the sanitized SVG is rendered, with script execution occurring when a user activates the affected link; the default sanitizer configuration is not unconditionally affected. This issue is fixed in sanitize-html 2.18.0.