High advisory for rubygem-crass

Advisory overview

Crass is a pure Ruby CSS parser based on the CSS Syntax Level 3 spec. Security Fix(es): Crass is a Ruby CSS parser that is compliant with the CSS Syntax Level 3 specification. Prior to 1.0.8, Crass incorrectly treats a closing parenthesis after an escaped backslash as escaped while consuming the remnants of a bad URL. Crass therefore keeps declarations, style rules, or at-rules inside a bad URL token even though a browser treats them as live CSS. A sanitizer that parses untrusted CSS with Crass and reserializes it without rejecting the bad URL can allow CSS used for UI redress, external resource loading, or CSS-based data exfiltration, but this issue does not enable script execution in modern browsers. This issue is fixed in version 1.0.8.(CVE-2026-116695) Crass is a Ruby CSS parser that's fully compliant with the CSS Syntax Level 3 specification. Prior to 1.0.7, Crass recursively parses `CSS simple blocks and functions` without a depth guard. An attacker-controlled CSS value containing deeply nested blocks or functions can recurse until Ruby raises `SystemStackError`: stack level too deep, or cause excessive memory usage. Version 1.0.7 adds a configurable depth limit with a conservative default. This issue is fixed in version 1.0.7.(CVE-2026-61846) 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.(CVE-2026-61847) Crass is a Ruby CSS parser that's fully compliant with the CSS Syntax Level 3 specification. Prior to 1.0.7, when Crass parses input containing `non-ASCII characters`, inefficiencies in tracking the positions of `multi-byte characters` result in superlinear parsing time. An attacker-controlled CSS input consisting of many `non-ASCII characters` can therefore cause excessive CPU consumption and potentially denial of service. This issue is fixed in version 1.0.7.(CVE-2026-61848)

Affected packages and releases

Related references

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