CVE-2026-126207

CVSS 4.7 (medium) · published 2026-11-12

Loofah is a general library for manipulating and transforming HTML/XML documents and fragments, built on top of Nokogiri. Prior to 2.25.3, Loofah::HTML5::Scrub.scrub_css checks only the first parse of a style attribute, then rebuilds CSS with identifier escapes decoded so escaped parentheses, property names, comments, or quotes can become a live url() without a second safety check. An attacker can use list-style to make a viewer's browser request an attacker-chosen URL when content renders, or cursor to make the request on hover. The request can disclose the viewer's IP address, user agent, access timing, and access to internal-network hosts, but no script survives sanitization and the attacker cannot read the response. This issue is fixed in version 2.25.3.

Weakness: CWE-180, CWE-184

Source: NVD CVE-2026-126207

References

• https://github.com/flavorjones/loofah/commit/b198a36e44c9c5408163ac50787825e8ca0b166b
• https://github.com/flavorjones/loofah/pull/324
• https://github.com/flavorjones/loofah/releases/tag/v2.25.3
• https://github.com/flavorjones/loofah/security/advisories/GHSA-m3x9-938q-5767

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