{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "2.20.0"
              },
              {
                "fixed": "2.21.2"
              }
            ],
            "source": "AFFECTED_FIELD"
          },
          "events": [
            {
              "introduced": "13162921b89c4f662aa018771403457f069f7e26"
            },
            {
              "fixed": "5a32e4367ca5976f62af12887a09685b7109b054"
            }
          ],
          "repo": "https://github.com/ruby/json",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-9hj4-r449-hfvc"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-416"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/71xxx/CVE-2026-71847.json"
  },
  "details": "Ruby JSON is a JSON implementation for Ruby. From 2.20.0 until 2.21.2, Ruby's JSON native C extension clears the consumed JSON::ResumableParser input buffer but leaves state.start, state.cursor, and state.end pointing into released storage. When partial_value reconstructs an incomplete object containing duplicate keys, the duplicate-key warning path calls cursor_position, which dereferences those stale pointers. This results in a heap-use-after-free and can terminate the Ruby process. An attacker who can supply JSON stream data to an application using JSON::ResumableParser may cause process termination when the application calls partial_value on incomplete attacker-controlled input containing duplicate object keys. This issue has been fixed in version 2.21.2.",
  "id": "CVE-2026-71847",
  "modified": "2026-08-09T03:30:31.875664325Z",
  "published": "2026-08-07T18:31:28.507Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/71xxx/CVE-2026-71847.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/ruby/json/security/advisories/GHSA-9hj4-r449-hfvc"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-71847"
    }
  ],
  "schema_version": "1.8.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Ruby JSON: JSON::ResumableParser#partial_value dereferences a freed input buffer and crashes on truncated duplicate-key streams"
}