Security advisory

{
  "id": "ff5622630edd5da6898041a7d466ce13f6fa77f225d74abb7ab73f88140cca42",
  "url": "https://osv.dev/vulnerability/CVE-2021-28166",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2021-28166",
    "summary": "In Eclipse Mosquitto version 2.0.0 to 2.0.9, if an authenticated client that had connected with MQTT v5 sent a crafted CONNACK message to the broker, a NULL pointer dereference would occur.",
    "evidence": "osv:CVE-2021-28166",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2021-28166",
      "aliases": [
        "CVE-2021-28166"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/eclipse-mosquitto/mosquitto",
              "type": "GIT",
              "events": [
                {
                  "introduced": "c00671af5c25593bebf065ed8820f7f00ee85efe"
                },
                {
                  "last_affected": "c03c6b765e3af813d2001d21f95e0808f708d075"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:eclipse:mosquitto:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "2.0.0"
                      },
                      {
                        "last_affected": "2.0.9"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v2.0.9",
            "v2.0.8",
            "v2.0.7",
            "v2.0.6",
            "v2.0.5",
            "v2.0.4",
            "v2.0.3",
            "v2.0.2",
            "v2.0.1",
            "v2.0.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-28166.json"
          }
        }
      ],
      "modified": "2026-10-24T10:30:33.921073251Z",
      "provider": "osv",
      "references": [
        "https://bugs.eclipse.org/bugs/show_bug.cgi?id=572608"
      ],
      "provider_metadata": {}
    },
    "related_cves": [
      {
        "value": "CVE-2021-28166",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 433405,
  "published_at": "2021-04-07T19:15:12.347+00:00"
}