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CVE-2026-61846 — crass

Fix: rgrove/crass@cf68287

CVE-2026-61846 is a CWE-674 vulnerability in crass. A fix is available for crass — see the affected versions and patch details below.

Crass: Deeply nested CSS blocks and functions can trigger a SystemStackError or excessive memory usage

Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Oct 29, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Real-World Exposure

1 pkg affected
💎crass

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects RubyGems packages — download data is not available via public APIs for these ecosystems.

Description

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.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
💎RubyGemscrassall versions1.0.7bundle update crass --conservative

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for crass, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update crass to 1.0.7 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-61846 is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

### Impact Crass recursively parses CSS simple blocks and functions without a depth guard. An attacker-controlled value containing many deeply nested blocks can recurse until Ruby raises `SystemStackError: stack level too deep`, or can cause excessive memory usage. ### Patches This is fixed in Crass 1.0.7, which adds a configurable depth limit with a conservative default. ### Workarounds Add `SystemStackError` handling around Crass calls in your application. Buy more RAM.
O3 Security · Impact-Aware SCA

Is CVE-2026-61846 in your dependencies?

Find it across RubyGems, including transitive dependencies.

CVE-2026-61846: crass — Fixed in 1.0.7