GHSA-FFQ8-9J34-F4R6

Vulnerability from github – Published: 2026-07-19 18:31 – Updated: 2026-07-20 15:32
VLAI
Details

In the Linux kernel, the following vulnerability has been resolved:

Bluetooth: MGMT: validate Add Extended Advertising Data length

MGMT_OP_ADD_EXT_ADV_DATA is registered as a variable-length command, with MGMT_ADD_EXT_ADV_DATA_SIZE as the fixed header size. The handler then uses cp->adv_data_len and cp->scan_rsp_len to validate and copy cp->data, but it never checks that those bytes are part of the mgmt command payload.

A short command can therefore make add_ext_adv_data() pass an out-of-bounds pointer into tlv_data_is_valid(). If the bytes beyond the command buffer are addressable, they can also be copied into the advertising instance as scan response data, where the caller can read them back via MGMT_OP_GET_ADV_INSTANCE. The trigger requires CAP_NET_ADMIN in the initial user namespace; KASAN reports an 8-byte slab-out-of-bounds read.

Reject commands whose length does not match the fixed header plus both advertising data lengths before parsing cp->data.

Severity
7.3 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:L
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{
  "affected": [],
  "aliases": [
    "CVE-2026-64126"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-19T16:17:54Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: MGMT: validate Add Extended Advertising Data length\n\nMGMT_OP_ADD_EXT_ADV_DATA is registered as a variable-length command,\nwith MGMT_ADD_EXT_ADV_DATA_SIZE as the fixed header size.  The handler\nthen uses cp-\u003eadv_data_len and cp-\u003escan_rsp_len to validate and copy\ncp-\u003edata, but it never checks that those bytes are part of the mgmt\ncommand payload.\n\nA short command can therefore make add_ext_adv_data() pass an\nout-of-bounds pointer into tlv_data_is_valid().  If the bytes beyond\nthe command buffer are addressable, they can also be copied into the\nadvertising instance as scan response data, where the caller can read\nthem back via MGMT_OP_GET_ADV_INSTANCE.  The trigger requires\nCAP_NET_ADMIN in the initial user namespace; KASAN reports an 8-byte\nslab-out-of-bounds read.\n\nReject commands whose length does not match the fixed header plus both\nadvertising data lengths before parsing cp-\u003edata.",
  "id": "GHSA-ffq8-9j34-f4r6",
  "modified": "2026-07-20T15:32:01Z",
  "published": "2026-07-19T18:31:53Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64126"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0bc1a5a69f541859293d79db72bd7854ac48df51"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0d5104390b445e7bd664ad583837e4c04d892c9d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/14b01b9cba04e6ce82825f68fc4c4322fa4ffa43"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a143ce77a5292f2c9285137433d879ce71d190a7"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a6c75a3fad226ccbd8ef9110dee87c92c299f2ab"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d3f7d17960ed50df3a6709c5158caff989c8c905"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f1febe93ef075314615f970a87681d9ab86691d1"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:L",
      "type": "CVSS_V3"
    }
  ]
}



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