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CVE-2026-61846

Crass: Deeply nested CSS blocks and functions can trigger a SystemStackError or excessive memory usage

6.3 MediumFix available

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

0.49%Unchanged since Oct 31, 2026
90%50%10%1%

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 MediumCVSS: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 MediumCVSS: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 MediumCVSS: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 MediumCVSS: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 MediumCVSS: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 MediumCVSS: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 MediumCVSS: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 MediumCVSS: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

Affected packages
PackageAffectedFixed
crass
RubyGems
before 1.0.7
1.0.7
ruby-crass
Debian:12
All versions, plus listed versions
1.0.2-31.0.6-11.0.7-11.0.8-1
None known
ruby-crass
Debian:13
All versions, plus listed versions
1.0.6-11.0.7-11.0.8-1
None known
ruby-crass
Debian:14
before 1.0.7-1, plus listed versions
1.0.6-1
1.0.7-1
crass
RubyGems
before 1.0.7, plus listed versions
0.0.10.0.20.1.00.2.00.2.1
Show 7 moreShow less
1.0.01.0.11.0.21.0.31.0.41.0.51.0.6
1.0.7
ruby-crass
Ubuntu:16.04:LTS
All versions, plus listed versions
1.0.2-2
None known
ruby-crass
Ubuntu:18.04:LTS
All versions, plus listed versions
1.0.2-2
None known
ruby-crass
Ubuntu:20.04:LTS
All versions, plus listed versions
1.0.2-2
None known
ruby-crass
Ubuntu:22.04:LTS
All versions, plus listed versions
1.0.2-2.11.0.2-3
None known
ruby-crass
Ubuntu:24.04:LTS
All versions, plus listed versions
1.0.2-3
None known
ruby-crass
Ubuntu:26.10
All versions, plus listed versions
1.0.6-1ubuntu1
None known
ruby-crass
Ubuntu:26.04:LTS
All versions, plus listed versions
1.0.6-1ubuntu1
None known

History

History
WhenChangedSources
2026-11-04affected, aliases, facts, referencesOSV
2026-11-02createdCVE List, EUVD, GitHub Advisories, NVD, OSV

References

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