{
  "cveId": "CVE-2026-99139",
  "url": "https://patchblox.com/security/cve/CVE-2026-99139",
  "summary": "CVE-2026-99139 is fixed in linux on 1 platform, first by DEBIAN-CVE-2026-99139, released November 3, 2026. It is not reported as exploited. Patch Radar priority: High.",
  "title": "tcp: fix use-after-free in do_tcp_getsockopt(TCP_CONGESTION)",
  "description": "In the Linux kernel, the following vulnerability has been resolved:  tcp: fix use-after-free in do_tcp_getsockopt(TCP_CONGESTION)  do_tcp_getsockopt() reads icsk-\u003Eicsk_ca_ops-\u003Ename without holding rcu_read_lock(). Since commit 0baf26b0fcd7 (\u0022bpf: tcp: Support tcp_congestion_ops in bpf\u0022), icsk_ca_ops can point to dynamically allocated BPF struct_ops memory that may be freed concurrently via setsockopt(TCP_CONGESTION), leading to a use-after-free.    BUG: KASAN: slab-use-after-free in _copy_to_user\u002B0x37/0x60   Read of size 16 at addr ffff888013505260 by task exploit/149    _copy_to_user\u002B0x37/0x60    do_tcp_getsockopt\u002B0x158a/0x2460 (net/ipv4/tcp.c:4585)    tcp_getsockopt\u002B0x91/0xf0    __sys_getsockopt\u002B0xf7/0x170  Fix this by holding rcu_read_lock() around the ca_ops-\u003Ename access, using READ_ONCE() to load icsk_ca_ops, and copying the name to a stack buffer before releasing the lock. Also annotate the relevant icsk_ca_ops stores with WRITE_ONCE() to fix the accompanying KCSAN data-race issue.",
  "published": "2026-10-28T11:17:33Z",
  "severity": "Important",
  "cvss": 7.8,
  "epss": 0.00173,
  "epssPercentile": 0.06787,
  "priority": "High",
  "priorityTier": 3,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "vendorAdvisory": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-99139",
  "fixes": [
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 13.5 (trixie)",
      "fixedVersion": "6.12.115-2",
      "fix": "DEBIAN-CVE-2026-99139",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-99139",
      "released": "2026-11-03T18:58:21Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 14",
      "fixedVersion": "7.2.13-1",
      "fix": "DEBIAN-CVE-2026-99139",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-99139",
      "released": "2026-11-03T18:58:21Z"
    }
  ],
  "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"
  }
}