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[ CVE-2026-61847 · Published 30 Oct 2026 ]

Crass: A large number of adjacent CSS comments can trigger a SystemStackError

CVSS 6.3 EPSS <1%Fix available

[ Description ]Official description

Crass is a Ruby CSS parser that's fully compliant with the CSS Syntax Level 3 specification. Prior to 1.0.7, when the `:preserve_comments` option is not enabled, which is the default, Crass discards CSS comments by recursively consuming the next token. An attacker-provided stylesheet containing a very large number of adjacent comments can cause excessive recursion and trigger a `SystemStackError`, denying service to the parsing application. Preserving comments avoids this recursive path. This issue is fixed in version 1.0.7.

[ Fixes ]Fixes and patches

  • crass 1.0.7Fixed version · GitHub Advisories · rubygems package crass: upgrade to 1.0.7 or later (affected < 1.0.7)

[ Packages ]Affected open-source packages

[ References ]References