Crass: Incorrect tokenization of bad URLs enables CSS sanitizer bypass

{
  "id": "37ce63556a6a2d820840f6676a0a0ddf2f823e5512025b2a93203c5f4080c5d1",
  "url": "https://www.cve.org/CVERecord?id=CVE-2026-116695",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Crass: Incorrect tokenization of bad URLs enables CSS sanitizer bypass",
    "summary": "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.",
    "evidence": "cve:CVE-2026-116695",
    "products": [
      {
        "name": {
          "value": "crass",
          "evidence": "/containers/cna/affected/0/product"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": []
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-116695",
      "aliases": [
        "CVE-2026-116695"
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "version": "4.0",
            "baseScore": 5.3,
            "attackVector": "NETWORK",
            "baseSeverity": "MEDIUM",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N",
            "userInteraction": "PASSIVE",
            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "privilegesRequired": "NONE",
            "subIntegrityImpact": "LOW",
            "vulnIntegrityImpact": "NONE",
            "subAvailabilityImpact": "NONE",
            "vulnAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "LOW",
            "vulnConfidentialityImpact": "NONE"
          }
        }
      ],
      "affected": [
        {
          "vendor": "rgrove",
          "product": "crass",
          "versions": [
            {
              "status": "affected",
              "version": "< 1.0.8"
            }
          ]
        }
      ],
      "modified": "2026-10-27T20:10:34.010Z",
      "provider": "cve",
      "references": [
        "https://github.com/rgrove/crass/security/advisories/GHSA-pq4g-8rxf-4g29",
        "https://github.com/rgrove/crass/commit/689fc45c632fdf3803b2f4e844ffc9cca3b08f34",
        "https://github.com/rgrove/crass/releases/tag/v1.0.8"
      ],
      "provider_metadata": {
        "cna": {
          "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
          "shortName": "GitHub_M",
          "dateUpdated": "2026-10-27T20:10:34.010Z"
        }
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-116695",
        "evidence": "/cveMetadata/cveId"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/containers/cna/metrics"
  },
  "source_id": "core-cve",
  "document_id": 398626,
  "published_at": "2026-10-27T20:10:34.01+00:00"
}