{
  "cveId": "CVE-2021-34431",
  "url": "https://patchblox.com/security/cve/CVE-2021-34431",
  "summary": "CVE-2021-34431 is fixed in 4 products on 1 platform, first by libmosquitto1 1.6.9-1ubuntu0.1~esm1, released October 2, 2023. It is not reported as exploited. Patch Radar priority: Routine.",
  "title": "libmosquitto1: In Eclipse Mosquitto version 1.6 to 2.0.10, if an authenticated client that had connected with MQTT v5 sent a crafted...",
  "description": "In Eclipse Mosquitto version 1.6 to 2.0.10, if an authenticated client that had connected with MQTT v5 sent a crafted CONNECT message to the broker a memory leak would occur, which could be used to provide a DoS attack against the broker.",
  "published": "2021-07-22T07:15:00Z",
  "severity": "Medium",
  "epss": 0.01113,
  "epssPercentile": 0.66215,
  "priority": "Routine",
  "priorityTier": 4,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "fixes": [
    {
      "platform": "linux",
      "product": "libmosquitto1",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "1.6.9-1ubuntu0.1~esm1",
      "fix": "libmosquitto1 1.6.9-1ubuntu0.1~esm1",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-libmosquitto1-1.6.9-1ubuntu0.1-esm1",
      "released": "2023-10-02T13:15:00Z"
    },
    {
      "platform": "linux",
      "product": "libmosquittopp1",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "1.6.9-1ubuntu0.1~esm1",
      "fix": "libmosquittopp1 1.6.9-1ubuntu0.1~esm1",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-libmosquittopp1-1.6.9-1ubuntu0.1-esm1",
      "released": "2023-10-02T13:15:00Z"
    },
    {
      "platform": "linux",
      "product": "mosquitto",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "1.6.9-1ubuntu0.1~esm1",
      "fix": "mosquitto 1.6.9-1ubuntu0.1~esm1",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-mosquitto-1.6.9-1ubuntu0.1-esm1",
      "released": "2023-10-02T13:15:00Z"
    },
    {
      "platform": "linux",
      "product": "mosquitto-clients",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "1.6.9-1ubuntu0.1~esm1",
      "fix": "mosquitto-clients 1.6.9-1ubuntu0.1~esm1",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-mosquitto-clients-1.6.9-1ubuntu0.1-esm1",
      "released": "2023-10-02T13:15:00Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-09T13:31:49Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}