CVE-2026-113657: ApostropheCMS sanitize-html: SMIL animation namespace-prefix bypass allows javascript: URI injection (XSS)

CVE-2026-113657 · Severity: low · CVSS 3.7 · Published 2026-10-20

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.

Technologies: sanitize-html (npm). Vendors: npm.

Quick answers

Is CVE-2026-113657 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-113657 being exploited in the wild.
How severe is CVE-2026-113657?
Low severity, with a CVSS score of 3.7, published 20 October 2026.
Which products and versions are affected?
sanitize-html (npm) >= 2.17.7, < 2.18.0, SEMVER:introduced=2.17.7,fixed=2.18.0.
Is there a fix for CVE-2026-113657?
Yes. sanitize-html (npm): upgrade to 2.18.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
Am I affected by CVE-2026-113657?
Check whether you run sanitize-html (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • sanitize-html (npm): upgrade to 2.18.0 or later
    npm install sanitize-html@2.18.0

Affected products

  • sanitize-html (npm) >= 2.17.7, < 2.18.0, SEMVER:introduced=2.17.7,fixed=2.18.0

Identifiers

  • CVE-2026-113657
  • GHSA-374f-7chj-9948

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