CVE-2026-73648: rails-html-sanitizer: Possible XSS vulnerability with certain configurations

Severity: medium (CVSS 5.1 v4.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-08-13 · updated 2026-10-24
Weakness: CWE-79

Description

rails-html-sanitizer is responsible for sanitizing HTML fragments in Rails applications. From 1.0.3 until 1.7.1, Rails::HTML::PermitScrubber restricted SVG reference elements in SVG_ALLOW_LOCAL_HREF only when they used xlink:href, even though browsers also accept the plain href attribute. Applications with non-default allowed tags that included SVG use or feImage elements could therefore permit external references; a same-origin external SVG referenced by use could execute scripts in the sanitized document's context, while feImage could load external images for tracking. Applications using the default allowed tags are not affected. This issue is fixed in version 1.7.1.

Affected products

Rubygems Rails-Html-Sanitizer: from 1.0.3 before 1.7.1; 1.0.3, 1.0.4, 1.1.0, 1.2.0, 1.3.0, 1.4.0 (+11) — fixed in 1.7.1
rails-html-sanitizer: from 1.0.3, < 1.7.1

How to fix

Upgrade to a fixed version: Rubygems Rails-Html-Sanitizer 1.7.1. Check the vendor advisory for mitigations.

References

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