---
id: CVE-2026-64557
title: 'Bluetooth: L2CAP: Fix use-after-free in l2cap_sock_new_connection_cb()'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  Bluetooth: L2CAP: Fix use-after-free in l2cap_sock_new_connection_cb()

  l2cap_sock_new_connection_cb() returned l2cap_pi(sk)->chan after
  release_sock(parent). Once the …
severity: high
cvss: 8.8
cvssVector: 'CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cvssSource: cna
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 8ffb929098a56939ac71509302eeab5b207bf262 <
    b39298044e5534612511a2ff5de03ba5f6e7a820
  - >-
    Linux >= 8ffb929098a56939ac71509302eeab5b207bf262 <
    8c37e4338c801ebb8cee52436c01c41e009f6e87
  - >-
    Linux >= 8ffb929098a56939ac71509302eeab5b207bf262 <
    84e718b6a814edc84159361f9f454a4e92ae91ae
  - >-
    Linux >= 8ffb929098a56939ac71509302eeab5b207bf262 <
    36da806f7fbaee56ad9e81859deec203f9728700
  - >-
    Linux >= 8ffb929098a56939ac71509302eeab5b207bf262 <
    733e76e74e406c1d1ddc7369420dd8a47f48bb8a
  - >-
    Linux >= 8ffb929098a56939ac71509302eeab5b207bf262 <
    6fef032af0092ed5ccb767239a9ac1bc38c08a40
  - Linux 3.13
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-16T15:42:36.931417Z'
published: '2026-07-29'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T15:52:52.563Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-64557'
references:
  - url: 'https://git.kernel.org/stable/c/b39298044e5534612511a2ff5de03ba5f6e7a820'
  - url: 'https://git.kernel.org/stable/c/8c37e4338c801ebb8cee52436c01c41e009f6e87'
  - url: 'https://git.kernel.org/stable/c/84e718b6a814edc84159361f9f454a4e92ae91ae'
  - url: 'https://git.kernel.org/stable/c/36da806f7fbaee56ad9e81859deec203f9728700'
  - url: 'https://git.kernel.org/stable/c/733e76e74e406c1d1ddc7369420dd8a47f48bb8a'
  - url: 'https://git.kernel.org/stable/c/6fef032af0092ed5ccb767239a9ac1bc38c08a40'
tags:
  - cve.org
epss: 0.00241
epssPercentile: 0.1416
ingestedAt: '2026-10-16T17:24:46.834Z'
---

## Overview

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

Bluetooth: L2CAP: Fix use-after-free in l2cap_sock_new_connection_cb()

l2cap_sock_new_connection_cb() returned l2cap_pi(sk)->chan after
release_sock(parent). Once the parent lock is dropped the newly
enqueued child socket sk is reachable via the accept queue, so another
task can accept and free it before the callback dereferences sk,
resulting in a use-after-free.

Rework the ->new_connection() op so the core, rather than the callback,
owns the child channel's lifetime. The op now receives a pre-allocated
new_chan and returns an errno instead of allocating and returning a
channel. l2cap_new_connection() allocates the child channel and links
it into the conn list via __l2cap_chan_add() before invoking the
callback, so the conn-list reference keeps the channel alive once
release_sock(parent) exposes the socket to other tasks.

Channel configuration that was duplicated in l2cap_sock_init() and the
various new_connection callbacks is consolidated into
l2cap_chan_set_defaults(), which now inherits from the parent channel
when one is supplied.

## Affected

- `Linux >= 8ffb929098a56939ac71509302eeab5b207bf262 < b39298044e5534612511a2ff5de03ba5f6e7a820`
- `Linux >= 8ffb929098a56939ac71509302eeab5b207bf262 < 8c37e4338c801ebb8cee52436c01c41e009f6e87`
- `Linux >= 8ffb929098a56939ac71509302eeab5b207bf262 < 84e718b6a814edc84159361f9f454a4e92ae91ae`
- `Linux >= 8ffb929098a56939ac71509302eeab5b207bf262 < 36da806f7fbaee56ad9e81859deec203f9728700`
- `Linux >= 8ffb929098a56939ac71509302eeab5b207bf262 < 733e76e74e406c1d1ddc7369420dd8a47f48bb8a`
- `Linux >= 8ffb929098a56939ac71509302eeab5b207bf262 < 6fef032af0092ed5ccb767239a9ac1bc38c08a40`
- `Linux 3.13`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.