Security advisory

{
  "id": "f0afbf5ea64a188b2459fad263bca23a5a30fc09508df617c6b1fe2bf76dcaaf",
  "url": "https://osv.dev/vulnerability/CVE-2021-45936",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2021-45936",
    "summary": "wolfSSL wolfMQTT 1.9 has a heap-based buffer overflow in MqttDecode_Disconnect (called from MqttClient_DecodePacket and MqttClient_WaitType).",
    "evidence": "osv:CVE-2021-45936",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2021-45936",
      "aliases": [
        "CVE-2021-45936"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/wolfssl/wolfmqtt",
              "type": "GIT",
              "events": [
                {
                  "introduced": "74c09f7eb7934112cba2fe5a0b4956f2a01016af"
                },
                {
                  "last_affected": "74c09f7eb7934112cba2fe5a0b4956f2a01016af"
                },
                {
                  "fixed": "84d4b53122e0fa0280c7872350b89d5777dabbb2"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:wolfssl:wolfmqtt:1.9:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "1.9"
                      },
                      {
                        "last_affected": "1.9"
                      }
                    ],
                    "source": "CPE_STRING"
                  },
                  {
                    "range": [
                      {
                        "fixed": "84d4b53122e0fa0280c7872350b89d5777dabbb2"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "1.9",
            "v1.9"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-45936.json",
            "vanir_signatures": [
              {
                "id": "CVE-2021-45936-3c4f0149",
                "digest": {
                  "threshold": 0.9,
                  "line_hashes": [
                    "280277640168772996348933106240497287098",
                    "120079499844175725862248008020683433689",
                    "47346730709629407828913387344300580063",
                    "79204163782737757014109719066411078623",
                    "120803118586187991233588399328252326413"
                  ]
                },
                "source": "https://github.com/wolfssl/wolfmqtt/commit/84d4b53122e0fa0280c7872350b89d5777dabbb2",
                "target": {
                  "file": "src/mqtt_client.c"
                },
                "deprecated": false,
                "signature_type": "Line",
                "signature_version": "v1"
              },
              {
                "id": "CVE-2021-45936-7e8fea99",
                "digest": {
                  "length": 3755,
                  "function_hash": "329802369575170683440296892229791015484"
                },
                "source": "https://github.com/wolfssl/wolfmqtt/commit/84d4b53122e0fa0280c7872350b89d5777dabbb2",
                "target": {
                  "file": "src/mqtt_client.c",
                  "function": "MqttClient_WaitType"
                },
                "deprecated": false,
                "signature_type": "Function",
                "signature_version": "v1"
              }
            ],
            "vanir_signatures_modified": "2026-10-20T14:30:21Z"
          }
        }
      ],
      "modified": "2026-10-20T14:30:21.496390875Z",
      "provider": "osv",
      "references": [
        "https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=39053",
        "https://github.com/wolfSSL/wolfMQTT/commit/84d4b53122e0fa0280c7872350b89d5777dabbb2",
        "https://github.com/google/oss-fuzz-vulns/blob/main/vulns/wolfmqtt/OSV-2021-1348.yaml"
      ],
      "provider_metadata": {}
    },
    "related_cves": [
      {
        "value": "CVE-2021-45936",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 389245,
  "published_at": "2022-01-01T01:15:08.73+00:00"
}