Security advisory

{
  "id": "c18e57808be6fcc9931b6d99d21a50cb2383c5ebc5c58fbf8928103ca1fd56e3",
  "url": "https://osv.dev/vulnerability/CVE-2021-46878",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2021-46878",
    "summary": "An issue was discovered in Treasure Data Fluent Bit 1.7.1, erroneous parsing in flb_pack_msgpack_to_json_format leads to type confusion bug that interprets whatever is on the stack as msgpack maps and arrays, leading to use-after-free. This can be used by an attacker to craft a specially craft file and trick the victim opening it using the affect software, triggering use-after-free and execute arbitrary code on the target system.",
    "evidence": "osv:CVE-2021-46878",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2021-46878",
      "aliases": [
        "BIT-fluent-bit-2021-46878",
        "CVE-2021-46878"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/fluent/fluent-bit",
              "type": "GIT",
              "events": [
                {
                  "introduced": "7edd2235cd2da7fe76258b7faa59ee9b37f52f8b"
                },
                {
                  "last_affected": "7edd2235cd2da7fe76258b7faa59ee9b37f52f8b"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:treasuredata:fluent_bit:1.7.1:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "1.7.1"
                      },
                      {
                        "last_affected": "1.7.1"
                      }
                    ],
                    "source": "CPE_STRING"
                  }
                ]
              }
            }
          ],
          "versions": [
            "1.7.1",
            "v1.7.1"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-46878.json"
          }
        }
      ],
      "modified": "2026-10-20T10:55:11.455035003Z",
      "provider": "osv",
      "references": [
        "https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=27742",
        "https://github.com/fluent/fluent-bit/pull/3115"
      ],
      "provider_metadata": {}
    },
    "related_cves": [
      {
        "value": "CVE-2021-46878",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 387039,
  "published_at": "2023-04-11T18:15:58.34+00:00"
}