{
  "cveId": "CVE-2025-24356",
  "url": "https://patchblox.com/security/cve/CVE-2025-24356",
  "summary": "CVE-2025-24356 is fixed in fastd on 1 platform, first by DEBIAN-CVE-2025-24356, released January 27, 2025. It is not reported as exploited. Patch Radar priority: High.",
  "title": "fastd: fastd is a VPN daemon which tunnels IP packets and Ethernet frames over UDP",
  "description": "fastd is a VPN daemon which tunnels IP packets and Ethernet frames over UDP. When receiving a data packet from an unknown IP address/port combination, fastd will assume that one of its connected peers has moved to a new address and initiate a reconnect by sending a handshake packet. This \u0022fast reconnect\u0022 avoids having to wait for a session timeout (up to ~90s) until a new connection is established. Even a 1-byte UDP packet just containing the fastd packet type header can trigger a much larger handshake packet (~150 bytes of UDP payload). Including IPv4 and UDP headers, the resulting amplification factor is roughly 12-13. By sending data packets with a spoofed source address to fastd instances reachable on the internet, this amplification of UDP traffic might be used to facilitate a Distributed Denial of Service attack. This vulnerability is fixed in v23.",
  "published": "2025-01-27T18:15:41Z",
  "severity": "high",
  "cvss": 7.5,
  "cvssVector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
  "epss": 0.00708,
  "epssPercentile": 0.53736,
  "priority": "High",
  "priorityTier": 3,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "fixes": [
    {
      "platform": "linux",
      "product": "fastd",
      "release": "Debian 13.5 (trixie)",
      "fixedVersion": "23-1",
      "fix": "DEBIAN-CVE-2025-24356",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2025-24356",
      "released": "2025-01-27T18:15:41Z"
    },
    {
      "platform": "linux",
      "product": "fastd",
      "release": "Debian 14",
      "fixedVersion": "23-1",
      "fix": "DEBIAN-CVE-2025-24356",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2025-24356",
      "released": "2025-01-27T18:15:41Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-08T19:12:23Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}