Summary
Crass: A large number of adjacent CSS comments can trigger a SystemStackError
Workarounds
Set the :preserve_comments option to true if this is acceptable to your use case (recursion doesn't occur when comments are preserved).
Impact
When the :preserve_comments option is not enabled (which is the default behavior), Crass discards CSS comments by recursively consuming the next token. An attacker who provides a stylesheet containing a very large number of adjacent comments can cause excessive recursion and trigger a SystemStackError.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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This is fixed in Crass 1.0.7, which no longer recurses when discarding comments.
Frequently Asked Questions
- What is CVE-2026-61847? CVE-2026-61847 is a medium-severity security vulnerability in crass (rubygems), affecting versions < 1.0.7. It is fixed in 1.0.7.
- Which versions of crass are affected by CVE-2026-61847? crass (rubygems) versions < 1.0.7 is affected.
- Is there a fix for CVE-2026-61847? Yes. CVE-2026-61847 is fixed in 1.0.7. Upgrade to this version or later.
- Is CVE-2026-61847 exploitable, and should I be worried? Whether CVE-2026-61847 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-61847 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-61847? Upgrade
crassto 1.0.7 or later.