{
  "cveId": "CVE-2026-99179",
  "url": "https://patchblox.com/security/cve/CVE-2026-99179",
  "summary": "CVE-2026-99179 is fixed in linux on 1 platform, first by DEBIAN-CVE-2026-99179, released November 3, 2026. It is not reported as exploited. Patch Radar priority: Routine.",
  "title": "watch_queue: Fix note pool publication race in watch_queue_set_size()",
  "description": "In the Linux kernel, the following vulnerability has been resolved:  watch_queue: Fix note pool publication race in watch_queue_set_size()  There is a race between watch_queue_set_size() and post_one_notification(). watch_queue_set_size() publishes wqueue-\u003Enotes, notes_bitmap, nr_pages and nr_notes with plain stores, and post_one_notification() reads them with plain loads under a different lock, so nothing orders the four stores against the poster\u0027s loads: depending on the build, notes can be stored last (gcc 14 on x86-64 does this).  Since keyctl_watch_key() lets a watch attach to a queue before it is sized, post_one_notification() can already be running on another CPU at that moment: it reads nr_notes \u003E 0, passes its bounds check, and then reads notes while it is still NULL, dereferencing notes[0].  An unprivileged user triggers this reliably by watching one of its own keys through a notification pipe and racing ioctl(IOC_WATCH_QUEUE_SET_SIZE) on that pipe against keyctl(KEYCTL_SETPERM) on the key from another CPU, triggering:    BUG: kernel NULL pointer dereference, address: 0000000000000000   RIP: 0010:post_one_notification.isra.0\u002B0xa2/0x1e0   Call Trace:    __post_watch_notification\u002B0x148/0x180    keyctl_setperm_key\u002B0x119/0x130    do_syscall_64\u002B0x108/0x4c0    entry_SYSCALL_64_after_hwframe\u002B0x77/0x7f   Kernel panic - not syncing: Fatal exception in interrupt  Fix this by publishing nr_notes last with smp_store_release(), and by reading it once with smp_load_acquire() in post_one_notification() before the bitmap and the page array are touched.  A poster that observes a non-zero nr_notes then also observes the pool behind it; one that observes zero drops the notification as before.",
  "published": "2026-10-28T11:17:38Z",
  "severity": "Moderate",
  "cvss": 5.5,
  "epss": 0.00183,
  "epssPercentile": 0.0796,
  "priority": "Routine",
  "priorityTier": 4,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "vendorAdvisory": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-99179",
  "fixes": [
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 13.5 (trixie)",
      "fixedVersion": "6.12.115-2",
      "fix": "DEBIAN-CVE-2026-99179",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-99179",
      "released": "2026-11-03T18:58:21Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 14",
      "fixedVersion": "7.2.13-1",
      "fix": "DEBIAN-CVE-2026-99179",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-99179",
      "released": "2026-11-03T18:58:21Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-09T01:18:40Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}