6.3 Medium

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

CVE-2026-61846

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.

Assessment

CVSS: 6.3 (v4.0)
Severity: Medium
Known exploited: Not listed in CISA KEV
Exploit availability: Nothing found in Exploit-DB, Metasploit, Nuclei or public PoC repositories
Published: 29 October 2026
Last updated: 29 October 2026
Affected: rubygems · crass
Weakness: CWE-400

CVSS vectorCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:L

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