GHSA-85M8-5MHX-Q797

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

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

Bluetooth: ISO: serialize iso_sock_clear_timer with socket lock

iso_sock_close() calls iso_sock_clear_timer() before acquiring lock_sock(sk).

iso_sock_clear_timer() reads iso_pi(sk)->conn twice without the socket lock held:

if (!iso_pi(sk)->conn)
    return;
cancel_delayed_work(&iso_pi(sk)->conn->timeout_work);

Concurrently, iso_conn_del() executes under lock_sock(sk) and calls iso_chan_del(), which sets iso_pi(sk)->conn to NULL and may result in the final reference to the connection being dropped:

CPU0                         CPU1
----                         ----
iso_sock_clear_timer()
  if (conn != NULL) ...      lock_sock(sk)
                               iso_chan_del()
                               iso_pi(sk)->conn = NULL
  cancel_delayed_work(conn)  /* NULL deref or UAF */

iso_pi(sk)->conn is not stable across the unlock window, causing a NULL pointer dereference or use-after-free.

Serialize iso_sock_clear_timer() with the socket lock by moving it inside lock_sock()/release_sock(), matching the pattern used in iso_conn_del() and all other call sites.

Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Show details on source website
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{
  "affected": [],
  "aliases": [
    "CVE-2026-63945"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-19T16:17:13Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: ISO: serialize iso_sock_clear_timer with socket lock\n\niso_sock_close() calls iso_sock_clear_timer() before acquiring\nlock_sock(sk).\n\niso_sock_clear_timer() reads iso_pi(sk)-\u003econn twice without the\nsocket lock held:\n\n    if (!iso_pi(sk)-\u003econn)\n        return;\n    cancel_delayed_work(\u0026iso_pi(sk)-\u003econn-\u003etimeout_work);\n\nConcurrently, iso_conn_del() executes under lock_sock(sk) and calls\niso_chan_del(), which sets iso_pi(sk)-\u003econn to NULL and may result in\nthe final reference to the connection being dropped:\n\n    CPU0                         CPU1\n    ----                         ----\n    iso_sock_clear_timer()\n      if (conn != NULL) ...      lock_sock(sk)\n                                   iso_chan_del()\n                                   iso_pi(sk)-\u003econn = NULL\n      cancel_delayed_work(conn)  /* NULL deref or UAF */\n\niso_pi(sk)-\u003econn is not stable across the unlock window, causing a\nNULL pointer dereference or use-after-free.\n\nSerialize iso_sock_clear_timer() with the socket lock by moving it\ninside lock_sock()/release_sock(), matching the pattern used in\niso_conn_del() and all other call sites.",
  "id": "GHSA-85m8-5mhx-q797",
  "modified": "2026-07-20T15:31:53Z",
  "published": "2026-07-19T18:31:47Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-63945"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/35f68f36d9883d56dec21cf85f7556d4657fc393"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4b5f8e608749b7e8fa386c6e4301cf9272595859"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/51cb9dcfdf9a1bccf312ab2ae4b62db629f7dcd5"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/996c2104d0726a8fe584f85b3d6327197374a348"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/bc08c15746f25f41dd0508b25780d1e84acbb2ef"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d9cbf7144ec589a3f0cc91f74a1a1af2d2b14afa"
    }
  ],
  "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:H",
      "type": "CVSS_V3"
    }
  ]
}



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