GHSA-J62W-H52R-54CH

Vulnerability from github – Published: 2026-08-15 15:30 – Updated: 2026-08-19 18:32
VLAI
Details

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

Bluetooth: L2CAP: fix UAF in l2cap_le_connect_rsp

l2cap_le_connect_rsp() obtains a channel via __l2cap_get_chan_by_ident() but neither holds a reference nor uses l2cap_chan_hold_unless_zero() before locking and operating on it. A concurrent l2cap_chan_del() triggered by a remote disconnect can free the channel between the lookup and l2cap_chan_lock(), causing a use-after-free.

The BR/EDR counterpart l2cap_connect_rsp() and the sibling handler l2cap_le_command_rej() already use l2cap_chan_hold_unless_zero() to safely hold a reference, but l2cap_le_connect_rsp() was left unprotected.

Fix by adding l2cap_chan_hold_unless_zero() after the ident lookup and l2cap_chan_put() on the exit path, consistent with other L2CAP response handlers.

Severity
8.8 (High)
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
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{
  "affected": [],
  "aliases": [
    "CVE-2026-74540"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-15T13:17:59Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: L2CAP: fix UAF in l2cap_le_connect_rsp\n\nl2cap_le_connect_rsp() obtains a channel via\n__l2cap_get_chan_by_ident() but neither holds a reference nor uses\nl2cap_chan_hold_unless_zero() before locking and operating on it.\nA concurrent l2cap_chan_del() triggered by a remote disconnect can\nfree the channel between the lookup and l2cap_chan_lock(), causing\na use-after-free.\n\nThe BR/EDR counterpart l2cap_connect_rsp() and the sibling handler\nl2cap_le_command_rej() already use l2cap_chan_hold_unless_zero()\nto safely hold a reference, but l2cap_le_connect_rsp() was left\nunprotected.\n\nFix by adding l2cap_chan_hold_unless_zero() after the ident lookup\nand l2cap_chan_put() on the exit path, consistent with other L2CAP\nresponse handlers.",
  "id": "GHSA-j62w-h52r-54ch",
  "modified": "2026-08-19T18:32:30Z",
  "published": "2026-08-15T15:30:35Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-74540"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/09f447accc2570751e7d17f0dc0788b40d3edade"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/15d6c2367217a6a20b1abae9f38ded716bf620f1"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1818180fe12d6cec7a437bc59cde8efdf6b10250"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/522b730c62c53a1981604fd73524697fd347830d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/58e3c5289ad230a7e24ae4b0c7b43f5ee6e32136"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/8325eafb38c3dee5af329266393763693d17381b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c4740e7f23ff9a8210198d8b4703259e21b9f69d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/fd4c1e301bdec60a40728ea37de531cbccda501a"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}



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