Security advisory

{
  "id": "4c314d36a880f1b84ad87af50b9faf1fe4d70b397383825daba36332def1a7b5",
  "url": "https://osv.dev/vulnerability/CVE-2021-36088",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2021-36088",
    "summary": "Fluent Bit (aka fluent-bit) 1.7.0 through 1.7.4 has a double free in flb_free (called from flb_parser_json_do and flb_parser_do).",
    "evidence": "osv:CVE-2021-36088",
    "products": [],
    "severity": "critical",
    "structured": {
      "id": "CVE-2021-36088",
      "aliases": [
        "BIT-fluent-bit-2021-36088",
        "CVE-2021-36088"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/fluent/fluent-bit",
              "type": "GIT",
              "events": [
                {
                  "introduced": "1e8c00240903ebc71a9092313fd8b620e10632bc"
                },
                {
                  "last_affected": "d638a11725ecdaf683be6167709c4712559cde79"
                },
                {
                  "fixed": "22346a74c07ceb90296be872be2d53eb92252a54"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:treasuredata:fluent_bit:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "1.7.0"
                      },
                      {
                        "last_affected": "1.7.4"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "range": [
                      {
                        "fixed": "22346a74c07ceb90296be872be2d53eb92252a54"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v1.7.4",
            "v1.7.3",
            "v1.7.2",
            "v1.7.1",
            "v1.7.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-36088.json",
            "vanir_signatures": [
              {
                "id": "CVE-2021-36088-499d5e79",
                "digest": {
                  "length": 3135,
                  "function_hash": "210821138041969896772177572225236899808"
                },
                "source": "https://github.com/fluent/fluent-bit/commit/22346a74c07ceb90296be872be2d53eb92252a54",
                "target": {
                  "file": "src/flb_parser_json.c",
                  "function": "flb_parser_json_do"
                },
                "deprecated": false,
                "signature_type": "Function",
                "signature_version": "v1"
              },
              {
                "id": "CVE-2021-36088-9b9fd8dd",
                "digest": {
                  "threshold": 0.9,
                  "line_hashes": [
                    "15907375869919561542890800455146713837",
                    "131867673044224448459384144928554040927",
                    "335748199596119996638886818829781370693",
                    "278957610952940763889198036630583526137",
                    "87820120863783867503610716601233301250",
                    "254993689099306520172863457632602922762",
                    "327121976266765979669537015380649424712",
                    "170524752924377180888809407919478188063"
                  ]
                },
                "source": "https://github.com/fluent/fluent-bit/commit/22346a74c07ceb90296be872be2d53eb92252a54",
                "target": {
                  "file": "src/flb_parser_json.c"
                },
                "deprecated": false,
                "signature_type": "Line",
                "signature_version": "v1"
              }
            ],
            "vanir_signatures_modified": "2026-10-20T14:25:23Z"
          }
        }
      ],
      "modified": "2026-10-20T14:25:23.101649433Z",
      "provider": "osv",
      "references": [
        "https://github.com/google/oss-fuzz-vulns/blob/main/vulns/fluent-bit/OSV-2021-702.yaml",
        "https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=33750",
        "https://github.com/fluent/fluent-bit/commit/22346a74c07ceb90296be872be2d53eb92252a54",
        "https://github.com/fluent/fluent-bit/pull/3453"
      ],
      "provider_metadata": {}
    },
    "related_cves": [
      {
        "value": "CVE-2021-36088",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 388978,
  "published_at": "2021-07-01T03:15:08.847+00:00"
}