From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-cve-announce@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@kernel.org>
Subject: CVE-2026-80666: Bluetooth: sco: Fix a race condition in sco_sock_timeout()
Date: Fri, 28 Aug 2026 08:49:43 +0200 [thread overview]
Message-ID: <2026082847-CVE-2026-80666-9e93@gregkh> (raw)
From: Greg Kroah-Hartman <gregkh@kernel.org>
Description
===========
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: sco: Fix a race condition in sco_sock_timeout()
sco_sock_timeout() runs asynchronously and lock_sock(sk). If the socket
is closing while the timer is running, it holds the same lock
(lock_sock(sk)) twice, leading to a deadlock.
CPU 0 CPU 1
==================== ======================
sco_sock_close()
sco_sock_timeout()
lock_sock(sk) // <-- LOCK
__sco_sock_close()
sco_chan_del()
sco_conn_put()
sco_conn_free()
disable_delayed_work_sync()
lock(sk) // <-- SAME LOCK
Fix this by moving disable_delayed_work_sync() outside of lock_sock(sk),
ensuring that no lock_sock(sk) is held before sco_sock_timeout().
Lockdep splat:
WARNING: possible circular locking dependency detected
6.13.0-rc4 #7 Not tainted
syz-executor292/9514 is trying to acquire lock:
ffff8881115d5070 ((work_completion)(&(&conn->timeout_work)->work)){+.+.}-{0:0}, at: rcu_lock_acquire sect/v6.13-rc4/./include/linux/rcupdate.h:337 [inline]
ffff8881115d5070 ((work_completion)(&(&conn->timeout_work)->work)){+.+.}-{0:0}, at: rcu_read_lock sect/v6.13-rc4/./include/linux/rcupdate.h:849 [inline]
ffff8881115d5070 ((work_completion)(&(&conn->timeout_work)->work)){+.+.}-{0:0}, at: start_flush_work sect/v6.13-rc4/kernel/workqueue.c:4137 [inline]
ffff8881115d5070 ((work_completion)(&(&conn->timeout_work)->work)){+.+.}-{0:0}, at: __flush_work+0xd1/0xc40 sect/v6.13-rc4/kernel/workqueue.c:4195
but task is already holding lock:
ffff88807db3a258 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}, at: lock_sock sect/v6.13-rc4/./include/net/sock.h:1623 [inline]
ffff88807db3a258 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}, at: sco_sock_close+0x25/0x100 sect/v6.13-rc4/net/bluetooth/sco.c:524
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}:
lock_acquire+0x1c4/0x520 sect/v6.13-rc4/kernel/locking/lockdep.c:5849
lock_sock_nested+0x48/0x130 sect/v6.13-rc4/net/core/sock.c:3622
lock_sock sect/v6.13-rc4/./include/net/sock.h:1623 [inline]
sco_sock_timeout+0xbe/0x270 sect/v6.13-rc4/net/bluetooth/sco.c:158
process_one_work sect/v6.13-rc4/kernel/workqueue.c:3229 [inline]
process_scheduled_works+0xa99/0x18f0 sect/v6.13-rc4/kernel/workqueue.c:3310
worker_thread+0x8a9/0xd80 sect/v6.13-rc4/kernel/workqueue.c:3391
kthread+0x2c6/0x360 sect/v6.13-rc4/kernel/kthread.c:389
ret_from_fork+0x4e/0x80 sect/v6.13-rc4/arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 sect/v6.13-rc4/arch/x86/entry/entry_64.S:244
-> #0 ((work_completion)(&(&conn->timeout_work)->work)){+.+.}-{0:0}:
check_prev_add sect/v6.13-rc4/kernel/locking/lockdep.c:3161 [inline]
check_prevs_add sect/v6.13-rc4/kernel/locking/lockdep.c:3280 [inline]
validate_chain+0x1888/0x5760 sect/v6.13-rc4/kernel/locking/lockdep.c:3904
__lock_acquire+0x13b4/0x2120 sect/v6.13-rc4/kernel/locking/lockdep.c:5226
lock_acquire+0x1c4/0x520 sect/v6.13-rc4/kernel/locking/lockdep.c:5849
touch_work_lockdep_map sect/v6.13-rc4/kernel/workqueue.c:3909 [inline]
start_flush_work sect/v6.13-rc4/kernel/workqueue.c:4163 [inline]
__flush_work+0x70f/0xc40 sect/v6.13-rc4/kernel/workqueue.c:4195
__cancel_work_sync sect/v6.13-rc4/kernel/workqueue.c:4351 [inline]
disable_delayed_work_sync+0xbb/0xf0 sect/v6.13-rc4/kernel/workqueue.c:4514
sco_conn_free sect/v6.13-rc4/net/bluetooth/sco.c:95 [inline]
kref_put sect/v6.13-rc4/./include/linux/kref.h:65 [inline]
sco_conn_put+0x18f/0x270 sect/v6.13-rc4/net/bluetooth/sco.c:107
sco_chan_del+0xe2/0x210 sect/v6.13-rc4/net/bluetooth/sco.c:236
sco_sock_close+0x8f/0x100 sect/v6.13-rc4/net/bluetooth/sco.c:526
sco_sock_release+0x62/0x2d0 sect/v6.13-rc4/net/bluetooth/sco.c:1300
__sock_release+0xe1/0x2d0 sect/v6.13-rc4/net/socket.c:640
sock_close+0x1c/0x30 sect/v6.13-rc4/net/socket.c:1408
__fput+0x2bd/0xa80 sect/v6.13-rc4/fs/file_table.c:450
__fput_sync+0x15e/0x1c0 sect/v6.13-rc4/fs/file_table.c:535
__do_sys_close sect/v6.13-rc4/fs/open.c:1554 [inline]
__se_sys_close sect/v6.13-rc4/fs/open.c:1539 [inline]
__x64_sys_close+0x93/0x120 sect/v6.13-rc4/fs/open.c:1539
do_syscall_x64 sect/v6.13-rc4/arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xee/0x210 sect/v6.13-rc4/arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
The Linux kernel CVE team has assigned CVE-2026-80666 to this issue.
Affected and fixed versions
===========================
Issue introduced in 6.13 with commit e6720779ae612a14ac4ba7fe4fd5b27d900d932c and fixed in 6.18.40 with commit da4d8eea0c5f33ea35c0e1d9e5f3e439f3b987ce
Issue introduced in 6.13 with commit e6720779ae612a14ac4ba7fe4fd5b27d900d932c and fixed in 7.1.5 with commit a50da115b5888062d32c86a548a29b4e2559d7ec
Issue introduced in 6.13 with commit e6720779ae612a14ac4ba7fe4fd5b27d900d932c and fixed in 7.2 with commit 0f8a5dcc66648b6e1458a9f3ba4c5a0463a228fc
Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.
Unaffected versions might change over time as fixes are backported to
older supported kernel versions. The official CVE entry at
https://cve.org/CVERecord/?id=CVE-2026-80666
will be updated if fixes are backported, please check that for the most
up to date information about this issue.
Affected files
==============
The file(s) affected by this issue are:
net/bluetooth/sco.c
Mitigation
==========
The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes. Individual
changes are never tested alone, but rather are part of a larger kernel
release. Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all. If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
https://git.kernel.org/stable/c/da4d8eea0c5f33ea35c0e1d9e5f3e439f3b987ce
https://git.kernel.org/stable/c/a50da115b5888062d32c86a548a29b4e2559d7ec
https://git.kernel.org/stable/c/0f8a5dcc66648b6e1458a9f3ba4c5a0463a228fc
reply other threads:[~2026-08-28 6:52 UTC|newest]
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