{
  "cveId": "CVE-2021-47593",
  "url": "https://patchblox.com/security/cve/CVE-2021-47593",
  "summary": "CVE-2021-47593 is fixed in linux on 1 platform, first by DEBIAN-CVE-2021-47593, released June 19, 2024. It is not reported as exploited. Patch Radar priority: Routine.",
  "title": "linux: In the Linux kernel, the following vulnerability has been resolved:  mptcp: clear \u0027kern\u0027 flag from fallback sockets...",
  "description": "In the Linux kernel, the following vulnerability has been resolved:  mptcp: clear \u0027kern\u0027 flag from fallback sockets  The mptcp ULP extension relies on sk-\u003Esk_sock_kern being set correctly: It prevents setsockopt(fd, IPPROTO_TCP, TCP_ULP, \u0022mptcp\u0022, 6); from working for plain tcp sockets (any userspace-exposed socket).  But in case of fallback, accept() can return a plain tcp sk. In such case, sk is still tagged as \u0027kernel\u0027 and setsockopt will work.  This will crash the kernel, The subflow extension has a NULL ctx-\u003Econn mptcp socket:  BUG: KASAN: null-ptr-deref in subflow_data_ready\u002B0x181/0x2b0 Call Trace:  tcp_data_ready\u002B0xf8/0x370  [..]",
  "published": "2024-06-19T15:15:53Z",
  "severity": "medium",
  "cvss": 5.5,
  "cvssVector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
  "epss": 0.00246,
  "epssPercentile": 0.15997,
  "priority": "Routine",
  "priorityTier": 4,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "fixes": [
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 12.15 (bookworm)",
      "fixedVersion": "5.15.15-1",
      "fix": "DEBIAN-CVE-2021-47593",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2021-47593",
      "released": "2024-06-19T15:15:53Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 13.5 (trixie)",
      "fixedVersion": "5.15.15-1",
      "fix": "DEBIAN-CVE-2021-47593",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2021-47593",
      "released": "2024-06-19T15:15:53Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 14",
      "fixedVersion": "5.15.15-1",
      "fix": "DEBIAN-CVE-2021-47593",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2021-47593",
      "released": "2024-06-19T15:15:53Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-08T13:06:02Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}