Bug 2573327 (CVE-2026-128068)

Summary: CVE-2026-128068 rails-html-sanitizer: rails-html-sanitizer: Denial of Service via inefficient regular expression matching on SVG attributes
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Priority: medium    
Version: unspecifiedKeywords: Security
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OS: Linux   
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A flaw was found in rails-html-sanitizer. A remote attacker can exploit this vulnerability by submitting specially crafted HTML containing Scalable Vector Graphics (SVG) references, leading to a Denial of Service (DoS) condition. Due to an inefficient regular expression used when validating SVG reference attributes, processing input containing repeated whitespace can cause excessive CPU consumption. This issue primarily impacts configurations where applications customize allowed tags to permit SVG reference elements.
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Description OSIDB Bzimport 2026-11-13 17:33:36 UTC 
rails-html-sanitizer is responsible for sanitizing HTML fragments in Rails applications. From 1.0.3 through 1.7.1, Rails::HTML::PermitScrubber checks SVG href and xlink:href local references with a pattern whose line-start anchor and whitespace class cause an all-whitespace value to be rescanned from each line start. An attacker who supplies HTML can cause quadratic CPU consumption when an application customizes its allowed tags to include an SVG reference element such as use and permits href or xlink:href. The default allowed tag configuration is not affected. CRuby 3.2 and later uses linear-time regular expression matching for this pattern, while CRuby 3.1 and earlier and JRuby are affected. This issue is fixed in version 1.7.2.