flavorjones Loofah up to 2.25.2 HTML5 Sanitizer incorrect bitwise shift of integer

Summaryinfo

A vulnerability, which was classified as problematic, was found in flavorjones Loofah up to 2.25.2. Affected by this issue is some unknown functionality of the component HTML5 Sanitizer. The manipulation results in incorrect bitwise shift of integer. This vulnerability is identified as CVE-2026-126205. The attack can be executed remotely. There is not any exploit available. You should upgrade the affected component.

Detailsinfo

A vulnerability classified as problematic has been found in flavorjones Loofah up to 2.25.2. Affected is some unknown functionality of the component HTML5 Sanitizer. The manipulation with an unknown input leads to a incorrect bitwise shift of integer vulnerability. CWE is classifying the issue as CWE-1335. An integer value is specified to be shifted by a negative amount or an amount greater than or equal to the number of bits contained in the value. This is going to have an impact on availability. CVE summarizes:

Loofah is a general library for manipulating and transforming HTML/XML documents and fragments, built on top of Nokogiri. Prior to 2.25.3, the Loofah HTML5 sanitizer checks href and xlink:href on elements in SVG_ALLOW_LOCAL_HREF with a regular expression whose line anchor and newline-matching whitespace cause an all-whitespace value to be rescanned from every line start. An attacker can submit an SVG reference element with a long multiline-whitespace attribute and consume CPU quadratically during sanitization. CRuby 3.1 and earlier and JRuby are affected, while CRuby 3.2 and later uses linear-time regular-expression matching. The default safelist reaches the vulnerable check without a configuration change. This issue is fixed in version 2.25.3.

The advisory is shared for download at github.com. This vulnerability is traded as CVE-2026-126205 since 11/10/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. There are neither technical details nor an exploit publicly available.

Upgrading to version 2.25.3 eliminates this vulnerability.

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Productinfo

Vendor

• flavorjones

Name

• Loofah

Version

• 2.25.0
• 2.25.1
• 2.25.2

Website

• Product: https://github.com/flavorjones/loofah/

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