Quick answers
- Is CVE-2026-61847 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-61847 being exploited in the wild.
- How severe is CVE-2026-61847?
- Medium severity, with a CVSS score of 4, published 30 October 2026.
- Which products and versions are affected?
- Rgrove Crass < 1.0.7; crass (RubyGems) < 1.0.7, ECOSYSTEM:introduced=0,fixed=1.0.7.
- Is there a fix for CVE-2026-61847?
- Yes. crass (RubyGems): upgrade to 1.0.7 or later. Until then: Set the `:preserve_comments` option to `true` if acceptable for your use case, as recursion does not occur when comments are preserved. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-61847 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-61847?
- Check whether you run Rgrove Crass or crass (RubyGems) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
How to fix
- crass (RubyGems): upgrade to 1.0.7 or later
bundle update crass
Set the `:preserve_comments` option to `true` if acceptable for your use case, as recursion does not occur when comments are preserved.
Technical details
The vulnerability is an uncontrolled recursion flaw (CWE-674) in Crass's comment-handling logic. When the `:preserve_comments` option is false, the parser recursively consumes tokens to discard comments; a stylesheet with many adjacent comments triggers excessive recursion and a SystemStackError. The attack requires only network access to an application that processes untrusted CSS with default settings.
Affected products
- rgrove Crass < 1.0.7
Identifiers
- CVE-2026-61847
- GHSA-wwpr-jff3-395c
Timeline
- 2026-10-29: disclosed
- 2026-10-29: advisory
- 2026-06-25: patched