Crass : Large numeric exponents cause CPU and memory denial of service
CVE-2026-61845 · GHSA-6wmf-3r64-vcwv · published 20 Oct 2026
How serious is it
- Severity: high, CVSS score 8.9 out of 10.
- No exploit prediction (EPSS) score yet.
- Not on the CISA list of exploited vulnerabilities.
- No public exploit in Exploit-DB.
Is your app affected by CVE-2026-61845?
Paste this prompt into Claude Code, Cursor or any AI coding tool: it runs a free Shippable scan of your project and fixes what it finds. Built with Lovable, Bolt or v0? Scan your live app. Or upload your package file.
Who is affected
crass(RubyGems) < 1.0.7
How to check
- Run
bundle info crassin your project to see the installed version, including copies pulled in by other packages. - Or paste your lockfile into the checker: it lists every package with a known vulnerability, this one included.
How to fix
Copies a prompt for Claude Code, Cursor or Codex: it checks your lockfiles for this and upgrades it.
- Upgrade
crassto 1.0.7 or later, commit the lockfile and redeploy. - If a vulnerable version was live, check your logs and rotate the secrets that server could read.
The advisory
### Impact
Crass converts CSS scientific notation number values with unbounded exponentiation before it clamps the result to `Float::MAX`. Applications that use Crass to parse attacker-controlled CSS strings can be forced to spend disproportionate CPU and memory parsing a tiny input, possibly resulting in a crash.
### Patches
This is fixed in Crass 1.0.7.
### Related
- https://github.com/rubysec/ruby-advisory-db/blob/master/gems/crass/GHSA-6wmf-3r64-vcwv.yml
Check your whole app
Dependencies are only half of it. Free and read-only: before you push, run npx shippable-dev scan localhost:3000 in your project folder, no account needed. For your live app, you prove it's yours with a one-line tag first.
References
- github.com/rgrove/crass/security/advisories/GHSA-6wmf-3r64-vcwv
- github.com/rgrove/crass/releases/tag/v1.0.7
- github.com/rubysec/ruby-advisory-db/blob/master/gems/crass/GHSA-6wmf-3r64-vcwv.yml
- rubygems.org/gems/crass/versions/1.0.7
- github.com/advisories/GHSA-6wmf-3r64-vcwv
Merged from GitHub Advisory Database. Last updated 23 Oct 2026. All vulnerabilities · RSS · JSON