---
id: CVE-2025-39982
title: 'Bluetooth: hci_event: Fix UAF in hci_acl_create_conn_sync'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  Bluetooth: hci_event: Fix UAF in hci_acl_create_conn_sync

  This fixes the following UFA in hci_acl_create_conn_sync where a
  connection still pending is command submissi…
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 >= aef2aa4fa98e18ea5d9345bf777ee698c8598728 <
    6243bda271a628c48875e3e473206e7f584892ce
  - >-
    Linux >= aef2aa4fa98e18ea5d9345bf777ee698c8598728 <
    bcce99f613163a43de24674b717e7a6c135fc879
  - >-
    Linux >= aef2aa4fa98e18ea5d9345bf777ee698c8598728 <
    484c7d571a3d1b3fd298fa691b660438c4548a53
  - >-
    Linux >= aef2aa4fa98e18ea5d9345bf777ee698c8598728 <
    a78fd4fc5694ecb3b97deb2ad9eaebd67b4d2b08
  - >-
    Linux >= aef2aa4fa98e18ea5d9345bf777ee698c8598728 <
    9e622804d57e2d08f0271200606bd1270f75126f
  - Linux 5.18
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-15T21:55:51.666498Z'
published: '2025-10-15'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T22:02:35.601Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2025-39982'
references:
  - url: 'https://git.kernel.org/stable/c/6243bda271a628c48875e3e473206e7f584892ce'
  - url: 'https://git.kernel.org/stable/c/bcce99f613163a43de24674b717e7a6c135fc879'
  - url: 'https://git.kernel.org/stable/c/484c7d571a3d1b3fd298fa691b660438c4548a53'
  - url: 'https://git.kernel.org/stable/c/a78fd4fc5694ecb3b97deb2ad9eaebd67b4d2b08'
  - url: 'https://git.kernel.org/stable/c/9e622804d57e2d08f0271200606bd1270f75126f'
tags:
  - cve.org
epss: 0.00282
epssPercentile: 0.20552
ingestedAt: '2026-10-15T22:48:25.535Z'
---

## Overview

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

Bluetooth: hci_event: Fix UAF in hci_acl_create_conn_sync

This fixes the following UFA in hci_acl_create_conn_sync where a
connection still pending is command submission (conn->state == BT_OPEN)
maybe freed, also since this also can happen with the likes of
hci_le_create_conn_sync fix it as well:

BUG: KASAN: slab-use-after-free in hci_acl_create_conn_sync+0x5ef/0x790 net/bluetooth/hci_sync.c:6861
Write of size 2 at addr ffff88805ffcc038 by task kworker/u11:2/9541

CPU: 1 UID: 0 PID: 9541 Comm: kworker/u11:2 Not tainted 6.16.0-rc7 #3 PREEMPT(full)
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014
Workqueue: hci3 hci_cmd_sync_work
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xca/0x230 mm/kasan/report.c:480
 kasan_report+0x118/0x150 mm/kasan/report.c:593
 hci_acl_create_conn_sync+0x5ef/0x790 net/bluetooth/hci_sync.c:6861
 hci_cmd_sync_work+0x210/0x3a0 net/bluetooth/hci_sync.c:332
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 home/kwqcheii/source/fuzzing/kernel/kasan/linux-6.16-rc7/arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 123736:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:394
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __kmalloc_cache_noprof+0x230/0x3d0 mm/slub.c:4359
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 __hci_conn_add+0x233/0x1b30 net/bluetooth/hci_conn.c:939
 hci_conn_add_unset net/bluetooth/hci_conn.c:1051 [inline]
 hci_connect_acl+0x16c/0x4e0 net/bluetooth/hci_conn.c:1634
 pair_device+0x418/0xa70 net/bluetooth/mgmt.c:3556
 hci_mgmt_cmd+0x9c9/0xef0 net/bluetooth/hci_sock.c:1719
 hci_sock_sendmsg+0x6ca/0xef0 net/bluetooth/hci_sock.c:1839
 sock_sendmsg_nosec net/socket.c:712 [inline]
 __sock_sendmsg+0x219/0x270 net/socket.c:727
 sock_write_iter+0x258/0x330 net/socket.c:1131
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0x54b/0xa90 fs/read_write.c:686
 ksys_write+0x145/0x250 fs/read_write.c:738
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 103680:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x62/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2381 [inline]
 slab_free mm/slub.c:4643 [inline]
 kfree+0x18e/0x440 mm/slub.c:4842
 device_release+0x9c/0x1c0
 kobject_cleanup lib/kobject.c:689 [inline]
 kobject_release lib/kobject.c:720 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x22b/0x480 lib/kobject.c:737
 hci_conn_cleanup net/bluetooth/hci_conn.c:175 [inline]
 hci_conn_del+0x8ff/0xcb0 net/bluetooth/hci_conn.c:1173
 hci_conn_complete_evt+0x3c7/0x1040 net/bluetooth/hci_event.c:3199
 hci_event_func net/bluetooth/hci_event.c:7477 [inline]
 hci_event_packet+0x7e0/0x1200 net/bluetooth/hci_event.c:7531
 hci_rx_work+0x46a/0xe80 net/bluetooth/hci_core.c:4070
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 home/kwqcheii/sour
---truncated---

## Affected

- `Linux >= aef2aa4fa98e18ea5d9345bf777ee698c8598728 < 6243bda271a628c48875e3e473206e7f584892ce`
- `Linux >= aef2aa4fa98e18ea5d9345bf777ee698c8598728 < bcce99f613163a43de24674b717e7a6c135fc879`
- `Linux >= aef2aa4fa98e18ea5d9345bf777ee698c8598728 < 484c7d571a3d1b3fd298fa691b660438c4548a53`
- `Linux >= aef2aa4fa98e18ea5d9345bf777ee698c8598728 < a78fd4fc5694ecb3b97deb2ad9eaebd67b4d2b08`
- `Linux >= aef2aa4fa98e18ea5d9345bf777ee698c8598728 < 9e622804d57e2d08f0271200606bd1270f75126f`
- `Linux 5.18`

## Remediation

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