{
  "cveId": "CVE-2026-99163",
  "url": "https://patchblox.com/security/cve/CVE-2026-99163",
  "summary": "CVE-2026-99163 is fixed in linux on 1 platform, first by DEBIAN-CVE-2026-99163, released November 3, 2026. It is not reported as exploited. Patch Radar priority: High.",
  "title": "tracing/histograms: Reject non-stacktrace fields for synthetic stacktrace fields",
  "description": "In the Linux kernel, the following vulnerability has been resolved:  tracing/histograms: Reject non-stacktrace fields for synthetic stacktrace fields  In check_synth_field(), when a synthetic event field is a stacktrace (field-\u003Eis_stack) and the histogram field is not a \u0022long[\u0022 stacktrace array, validation falls through to the generic size and signedness comparison.  Because parse_synth_field() sets a stacktrace field\u0027s type to \u0022__data_loc unsigned long[]\u0022, its size is sizeof(u64) and synth_field_signed() marks it as signed.  Consequently, any 8-byte signed scalar histogram field passes the fallback check, and its scalar value is subsequently dereferenced as a kernel stacktrace pointer in get_field_size() and trace_stack().  Furthermore, checking strstr(hist_field-\u003Etype, \u0022long[\u0022) is insufficient because tracepoint fields defined with __bitmask() or __rel_bitmask() also have type \u0022__data_loc unsigned long[]\u0022 or \u0022__rel_loc unsigned long[]\u0022, whilst create_hist_field() treats them as 4-byte scalar values without HIST_FIELD_FL_STACKTRACE.  Propagate HIST_FIELD_FL_STACKTRACE to variable references and field variables (whilst excluding variable aliases from per-element stacktrace capture), and reject any mismatch between HIST_FIELD_FL_STACKTRACE and field-\u003Eis_stack in check_synth_field().",
  "published": "2026-10-28T11:17:36Z",
  "severity": "Moderate",
  "cvss": 7.8,
  "cvssVector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
  "epss": 0.00134,
  "epssPercentile": 0.0294,
  "priority": "High",
  "priorityTier": 3,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "vendorAdvisory": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-99163",
  "fixes": [
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 13.5 (trixie)",
      "fixedVersion": "6.12.115-2",
      "fix": "DEBIAN-CVE-2026-99163",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-99163",
      "released": "2026-11-03T18:58:21Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 14",
      "fixedVersion": "7.2.13-1",
      "fix": "DEBIAN-CVE-2026-99163",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-99163",
      "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"
  }
}