Description
Crass is a Ruby CSS parser that is compliant with the CSS Syntax Level 3 specification. Prior to 1.0.8, Crass incorrectly treats a closing parenthesis after an escaped backslash as escaped while consuming the remnants of a bad URL. Crass therefore keeps declarations, style rules, or at-rules inside a bad URL token even though a browser treats them as live CSS. A sanitizer that parses untrusted CSS with Crass and reserializes it without rejecting the bad URL can allow CSS used for UI redress, external resource loading, or CSS-based data exfiltration, but this issue does not enable script execution in modern browsers. This issue is fixed in version 1.0.8.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| rgrove | crass | < 1.0.8 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | ruby-crass | 1.0.8-1 | — |
| Debian 13 | ruby-crass | No fix yet | — |
| Debian 12 | ruby-crass | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | ruby-crass | No fix yet | — |
| Ubuntu 26.04 LTS | ruby-crass | No fix yet | — |
| Ubuntu 24.04 LTS | ruby-crass | No fix yet | — |
| Ubuntu 22.04 LTS | ruby-crass | No fix yet | — |
| Ubuntu 20.04 LTS | ruby-crass | No fix yet | — |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 18.04 LTS | ruby-crass | No fix yet | — |
| Ubuntu 16.04 LTS | ruby-crass | No fix yet | — |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| RubyGems | crass | < 1.0.8 | 1.0.8 | GHSA-pq4g-8rxf-4g29 |