Vulnerability-Lookup

GHSA-WWPR-JFF3-395C

Vulnerability from github – Published: 2026-10-29 16:35 – Updated: 2026-10-29 16:35

Summary

Crass: A large number of adjacent CSS comments can trigger a SystemStackError

Details

Impact

When the :preserve_comments option is not enabled (which is the default behavior), Crass discards CSS comments by recursively consuming the next token. An attacker who provides a stylesheet containing a very large number of adjacent comments can cause excessive recursion and trigger a SystemStackError.

Patches

This is fixed in Crass 1.0.7, which no longer recurses when discarding comments.

Workarounds

Set the :preserve_comments option to true if this is acceptable to your use case (recursion doesn't occur when comments are preserved).

Severity

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

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{
  "affected": [
    {
      "package": {
        "ecosystem": "RubyGems",
        "name": "crass"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.0.7"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-61847"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-674"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-10-29T16:35:23Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "### Impact\n\nWhen the `:preserve_comments` option is not enabled (which is the default behavior), Crass discards CSS comments by recursively consuming the next token. An attacker who provides a stylesheet containing a very large number of adjacent comments can cause excessive recursion and trigger a `SystemStackError`.\n\n### Patches\n\nThis is fixed in Crass 1.0.7, which no longer recurses when discarding comments.\n\n### Workarounds\n\nSet the `:preserve_comments` option to `true` if this is acceptable to your use case (recursion doesn\u0027t occur when comments are preserved).",
  "id": "GHSA-wwpr-jff3-395c",
  "modified": "2026-10-29T16:35:23Z",
  "published": "2026-10-29T16:35:23Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/rgrove/crass/security/advisories/GHSA-wwpr-jff3-395c"
    },
    {
      "type": "WEB",
      "url": "https://github.com/rgrove/crass/commit/25d78cc607c54262e9d43ea1930f3ba5bb03dfb5"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/rgrove/crass"
    },
    {
      "type": "WEB",
      "url": "https://github.com/rgrove/crass/releases/tag/v1.0.7"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "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",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Crass: A large number of adjacent CSS comments can trigger a SystemStackError"
}

CVE-2026-61847 (GCVE-0-2026-61847)

Vulnerability from cvelistv5 – Published: 2026-10-30 18:44 – Updated: 2026-10-30 22:15

Title

Crass: A large number of adjacent CSS comments can trigger a SystemStackError

Summary

Crass is a Ruby CSS parser that's fully compliant with the CSS Syntax Level 3 specification. Prior to 1.0.7, when the `:preserve_comments` option is not enabled, which is the default, Crass discards CSS comments by recursively consuming the next token. An attacker-provided stylesheet containing a very large number of adjacent comments can cause excessive recursion and trigger a `SystemStackError`, denying service to the parsing application. Preserving comments avoids this recursive path. This issue is fixed in version 1.0.7.

Severity

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

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-10-30 21:18 UTC

CWE

CWE-674 - Uncontrolled Recursion

Assigner

GitHub_M CNA under the mitre root

CNA scorecard C 72/100 over 7980 records in the last 180 days details

References

3 references

URL	Tags
https://github.com/rgrove/crass/security/advisori…	x_refsource_CONFIRM
https://github.com/rgrove/crass/commit/25d78cc607…	x_refsource_MISC
https://github.com/rgrove/crass/releases/tag/v1.0.7	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
rgrove	crass	Affected: < 1.0.7

Show details on NVD website

JSON

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{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-61847",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-10-30T21:18:11.231526Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-10-30T22:15:42.844Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "crass",
          "vendor": "rgrove",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 1.0.7"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Crass is a Ruby CSS parser that\u0027s fully compliant with the CSS Syntax Level 3 specification. Prior to 1.0.7, when the `:preserve_comments` option is not enabled, which is the default, Crass discards CSS comments by recursively consuming the next token. An attacker-provided stylesheet containing a very large number of adjacent comments can cause excessive recursion and trigger a `SystemStackError`, denying service to the parsing application. Preserving comments avoids this recursive path. This issue is fixed in version 1.0.7."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "attackComplexity": "LOW",
            "attackRequirements": "PRESENT",
            "attackVector": "NETWORK",
            "baseScore": 6.3,
            "baseSeverity": "MEDIUM",
            "privilegesRequired": "NONE",
            "subAvailabilityImpact": "LOW",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "vectorString": "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",
            "version": "4.0",
            "vulnAvailabilityImpact": "LOW",
            "vulnConfidentialityImpact": "NONE",
            "vulnIntegrityImpact": "NONE"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-674",
              "description": "CWE-674: Uncontrolled Recursion",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-30T18:44:22.330Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/rgrove/crass/security/advisories/GHSA-wwpr-jff3-395c",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/rgrove/crass/security/advisories/GHSA-wwpr-jff3-395c"
        },
        {
          "name": "https://github.com/rgrove/crass/commit/25d78cc607c54262e9d43ea1930f3ba5bb03dfb5",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/rgrove/crass/commit/25d78cc607c54262e9d43ea1930f3ba5bb03dfb5"
        },
        {
          "name": "https://github.com/rgrove/crass/releases/tag/v1.0.7",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/rgrove/crass/releases/tag/v1.0.7"
        }
      ],
      "source": {
        "advisory": "GHSA-wwpr-jff3-395c",
        "discovery": "UNKNOWN"
      },
      "title": "Crass: A large number of adjacent CSS comments can trigger a SystemStackError"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-61847",
    "datePublished": "2026-10-30T18:44:22.330Z",
    "dateReserved": "2026-07-10T20:28:17.513Z",
    "dateUpdated": "2026-10-30T22:15:42.844Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Vulnerability timeline

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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

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