CVE-2026-61846
Crass: Deeply nested CSS blocks and functions can trigger a SystemStackError or excessive memory usage
CVE-2026-61846 is a medium vulnerability (CVSS 6.3) in Rgrove Crass, published October 29, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.49%, the 41st percentile. Fixed in crass 1.0.7.
Crass is a Ruby CSS parser that's fully compliant with the CSS Syntax Level 3 specification. Prior to 1.0.7, Crass recursively parses CSS simple blocks and functions without a depth guard. An attacker-controlled CSS value containing deeply nested blocks or functions can recurse until Ruby raises SystemStackError: stack level too deep, or cause excessive memory usage. Version 1.0.7 adds a configurable depth limit with a conservative default. This issue is fixed in version 1.0.7.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- Low
Exploit likelihood
What each source reports
CVE List Score used
6.3
Crass: Deeply nested CSS blocks and functions can trigger a SystemStackError or excessive memory usage
Crass is a Ruby CSS parser that's fully compliant with the CSS Syntax Level 3 specification. Prior to 1.0.7, Crass recursively parses CSS simple blocks and functions without a depth guard. An attacker-controlled CSS value containing deeply nested blocks or functions can recurse until Ruby raises SystemStackError: stack level too deep, or cause excessive memory usage. Version 1.0.7 adds a configurable depth limit with a conservative default. This issue is fixed in version 1.0.7.
- Record
CVE-2026-61846- CVSS 4.0
- 6.3 Medium
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:L - Weakness
- CWE-674
- Updated
- 2026-11-02
EUVDEUVD-2026-114322
6.3
Crass is a Ruby CSS parser that's fully compliant with the CSS Syntax Level 3 specification. Prior to 1.0.7, Crass recursively parses CSS simple blocks and functions without a depth guard. An attacker-controlled CSS value containing deeply nested blocks or functions can recurse until Ruby raises SystemStackError: stack level too deep, or cause excessive memory usage. Version 1.0.7 adds a configurable depth limit with a conservative default. This issue is fixed in version 1.0.7.
- Record
EUVD-2026-114322- CVSS 4.0
- 6.3 Medium
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:L - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-6jxj-px6v-747w
6.3
Crass: Deeply nested CSS blocks and functions can trigger a SystemStackError or excessive memory usage
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.
- Record
GHSA-6jxj-px6v-747w- CVSS 4.0
- 6.3 Medium
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:L - Weakness
- CWE-400
- Updated
- 2026-11-02
NVD
6.3
Crass is a Ruby CSS parser that's fully compliant with the CSS Syntax Level 3 specification. Prior to 1.0.7, Crass recursively parses CSS simple blocks and functions without a depth guard. An attacker-controlled CSS value containing deeply nested blocks or functions can recurse until Ruby raises SystemStackError: stack level too deep, or cause excessive memory usage. Version 1.0.7 adds a configurable depth limit with a conservative default. This issue is fixed in version 1.0.7.
- Record
CVE-2026-61846- CVSS 4.0
- 6.3 Medium
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - Weakness
- CWE-674
- Updated
- 2026-11-02
OSV
6.3
Crass: Deeply nested CSS blocks and functions can trigger a SystemStackError or excessive memory usage
Crass is a Ruby CSS parser that's fully compliant with the CSS Syntax Level 3 specification. Prior to 1.0.7, Crass recursively parses CSS simple blocks and functions without a depth guard. An attacker-controlled CSS value containing deeply nested blocks or functions can recurse until Ruby raises SystemStackError: stack level too deep, or cause excessive memory usage. Version 1.0.7 adds a configurable depth limit with a conservative default. This issue is fixed in version 1.0.7.
- Record
CVE-2026-61846- CVSS 4.0
- 6.3 Medium
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:L - Weakness
- CWE-674
- Updated
- 2026-11-02
OSVDEBIAN-CVE-2026-61846
6.3
Crass is a Ruby CSS parser that's fully compliant with the CSS Syntax Level 3 specification. Prior to 1.0.7, Crass recursively parses CSS simple blocks and functions without a depth guard. An attacker-controlled CSS value containing deeply nested blocks or functions can recurse until Ruby raises SystemStackError: stack level too deep, or cause excessive memory usage. Version 1.0.7 adds a configurable depth limit with a conservative default. This issue is fixed in version 1.0.7.
- Record
DEBIAN-CVE-2026-61846- CVSS 4.0
- 6.3 Medium
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - Updated
- 2026-11-02
OSVGHSA-6jxj-px6v-747w
6.3
Crass: Deeply nested CSS blocks and functions can trigger a SystemStackError or excessive memory usage
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.
- Record
GHSA-6jxj-px6v-747w- CVSS 4.0
- 6.3 Medium
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:L - Weakness
- CWE-400
- Updated
- 2026-11-02
OSVUBUNTU-CVE-2026-61846
6.3
Crass is a Ruby CSS parser that's fully compliant with the CSS Syntax Level 3 specification. Prior to 1.0.7, Crass recursively parses CSS simple blocks and functions without a depth guard. An attacker-controlled CSS value containing deeply nested blocks or functions can recurse until Ruby raises SystemStackError: stack level too deep, or cause excessive memory usage. Version 1.0.7 adds a configurable depth limit with a conservative default. This issue is fixed in version 1.0.7.
- Record
UBUNTU-CVE-2026-61846- CVSS 4.0
- 6.3 Medium
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:L - Updated
- 2026-11-04
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
crassRubyGems |
before 1.0.7 | 1.0.7 |
ruby-crassDebian:12 |
All versions, plus listed versions 1.0.2-31.0.6-11.0.7-11.0.8-1 |
None known |
ruby-crassDebian:13 |
All versions, plus listed versions 1.0.6-11.0.7-11.0.8-1 |
None known |
ruby-crassDebian:14 |
before 1.0.7-1, plus listed versions 1.0.6-1 |
1.0.7-1 |
crassRubyGems |
before 1.0.7, plus listed versions 0.0.10.0.20.1.00.2.00.2.1 Show 7 moreShow less1.0.01.0.11.0.21.0.31.0.41.0.51.0.6 |
1.0.7 |
ruby-crassUbuntu:16.04:LTS |
All versions, plus listed versions 1.0.2-2 |
None known |
ruby-crassUbuntu:18.04:LTS |
All versions, plus listed versions 1.0.2-2 |
None known |
ruby-crassUbuntu:20.04:LTS |
All versions, plus listed versions 1.0.2-2 |
None known |
ruby-crassUbuntu:22.04:LTS |
All versions, plus listed versions 1.0.2-2.11.0.2-3 |
None known |
ruby-crassUbuntu:24.04:LTS |
All versions, plus listed versions 1.0.2-3 |
None known |
ruby-crassUbuntu:26.10 |
All versions, plus listed versions 1.0.6-1ubuntu1 |
None known |
ruby-crassUbuntu:26.04:LTS |
All versions, plus listed versions 1.0.6-1ubuntu1 |
None known |
History
| When | Changed | Sources |
|---|---|---|
| 2026-11-04 | affected, aliases, facts, references | OSV |
| 2026-11-02 | created | CVE List, EUVD, GitHub Advisories, NVD, OSV |
References
github.com/rgrove/crass/security/advisories/GHSA-6jxj-px6v-747w
github.com/rgrove/crass/commit/cf68287356ec6e20d51cfc4a2d0c3912b7334e99
github.com/rgrove/crass/releases/tag/v1.0.7
github.com/advisories/GHSA-6jxj-px6v-747w
github.com/CVEProject/cvelistV5/tree/main/cves/2026/61xxx/CVE-2026-61846.json
nvd.nist.gov/vuln/detail/CVE-2026-61846