GHSA-HQ32-RPPJ-R4RV

Vulnerability from github – Published: 2026-06-25 09:31 – Updated: 2026-06-28 09:31
VLAI
Details

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

Bluetooth: RFCOMM: hold listener socket in rfcomm_connect_ind()

rfcomm_get_sock_by_channel() scans rfcomm_sk_list under the list lock, but returns the selected listener after dropping that lock without taking a reference. rfcomm_connect_ind() then locks the listener, queues a child socket on it, and may notify it after unlocking it.

The buggy scenario involves two paths, with each column showing the order within that path:

rfcomm_connect_ind(): listener close: 1. Find parent in 1. close() enters rfcomm_get_sock_by_channel() rfcomm_sock_release(). 2. Drop rfcomm_sk_list.lock 2. rfcomm_sock_shutdown() without pinning parent. closes the listener. 3. Call lock_sock(parent) and 3. rfcomm_sock_kill() bt_accept_enqueue(parent, unlinks and puts parent. sk, true). 4. Read parent flags and may 4. parent can be freed. call sk_state_change().

If close wins the race, parent can be freed before rfcomm_connect_ind() reaches lock_sock(), bt_accept_enqueue(), or the deferred-setup callback.

Take a reference on the listener before leaving rfcomm_sk_list.lock. After lock_sock() succeeds, recheck that it is still in BT_LISTEN before queueing a child, cache the deferred-setup bit while the parent is locked, and drop the reference after the last parent use.

KASAN reported a slab-use-after-free in lock_sock_nested() from rfcomm_connect_ind(), with the freeing stack going through rfcomm_sock_kill() and rfcomm_sock_release().

Severity
8.0 (High)
CVSS:3.1/AV:A/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-2026-53256"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-06-25T09:16:43Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: RFCOMM: hold listener socket in rfcomm_connect_ind()\n\nrfcomm_get_sock_by_channel() scans rfcomm_sk_list under the list lock,\nbut returns the selected listener after dropping that lock without\ntaking a reference. rfcomm_connect_ind() then locks the listener,\nqueues a child socket on it, and may notify it after unlocking it.\n\nThe buggy scenario involves two paths, with each column showing the\norder within that path:\n\nrfcomm_connect_ind():            listener close:\n  1. Find parent in              1. close() enters\n     rfcomm_get_sock_by_channel()   rfcomm_sock_release().\n  2. Drop rfcomm_sk_list.lock    2. rfcomm_sock_shutdown()\n     without pinning parent.        closes the listener.\n  3. Call lock_sock(parent) and  3. rfcomm_sock_kill()\n     bt_accept_enqueue(parent,      unlinks and puts parent.\n     sk, true).\n  4. Read parent flags and may   4. parent can be freed.\n     call sk_state_change().\n\nIf close wins the race, parent can be freed before\nrfcomm_connect_ind() reaches lock_sock(), bt_accept_enqueue(), or the\ndeferred-setup callback.\n\nTake a reference on the listener before leaving rfcomm_sk_list.lock.\nAfter lock_sock() succeeds, recheck that it is still in BT_LISTEN\nbefore queueing a child, cache the deferred-setup bit while the parent\nis locked, and drop the reference after the last parent use.\n\nKASAN reported a slab-use-after-free in lock_sock_nested() from\nrfcomm_connect_ind(), with the freeing stack going through\nrfcomm_sock_kill() and rfcomm_sock_release().",
  "id": "GHSA-hq32-rppj-r4rv",
  "modified": "2026-06-28T09:31:47Z",
  "published": "2026-06-25T09:31:22Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-53256"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1f73f92f66251065a5f39b09a47cf05ea14d3107"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/43c441edacf953b39517a44f5e5e10a93618b226"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6f4462d12133106460d7c046b95aad2491e3fddf"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/8802413ce63175fb522a2bd609fb043a3550c720"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a07d741c077d4e34b16458241a94d29039386553"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b0e33e409715c617e2a20f46f99aa5403a14dfda"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/de31973ef00e5aa55496f84cf6a44bb157a34e02"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f5ec76bdbeb80f75ad0be204371afffee0f8fac8"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}


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