OESA-2026-4760: rubygem-crass security update

Published Nov 11, 2026
·
Updated

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 :preservecomments 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 Software

1 affected componentFixes available
openeuler/rubygem-crass<1.0.8-1.oe2403sp4
1.0.8-1.oe2403sp4

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade openeuler/rubygem-crass to a version that resolves this vulnerability.

    Fixed in 1.0.8-1.oe2403sp4
  2. Upgrade

    Upgrade rubygem-crass to a version that resolves this vulnerability.

    Fixed in 1.0.8
  3. Configuration

    Enable the :preserve_comments option to preserve CSS comments and avoid the recursive comment-consumption path.

    Crass :preserve_comments = enabled

Event History

Nov 11, 2026
Advisory Published
via OSV·12:25 PM
Data Sourced
via OSV·12:25 PM
DescriptionSeverityAffected Software

Child vulnerabilities

Contains the following vulnerabilities.

Contact

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