CVE-2026-68394: Bluetooth: MGMT: revalidate LOAD_CONN_PARAM queued update

From: Greg Kroah-Hartman <[email protected]>

Description
===========

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

Bluetooth: MGMT: revalidate LOAD_CONN_PARAM queued update

MGMT_OP_LOAD_CONN_PARAM queues conn_update_sync() when a single parameter
update changes an existing LE central connection. The queued work currently
stores a borrowed hci_conn_params entry from hdev->le_conn_params. A later
LOAD_CONN_PARAM request can clear disabled parameters and free that entry
before hci_cmd_sync_work() runs the queued callback.

Do not keep the borrowed hci_conn_params pointer in queued work. Queue the
hci_conn instead and hold a reference until the queued callback completes.
When the work runs, revalidate that the connection is still present, look
up the current hci_conn_params entry, and cancel the update if userspace
removed that entry while the work was pending.

Copy the interval values from the current params entry under hdev->lock,
then drop the lock and keep using hci_le_conn_update_sync() to issue the
update.

Validation reproduced this kernel report:
BUG: KASAN: slab-use-after-free in conn_update_sync+0x2a/0xf0 [bluetooth]
Read of size 1 at addr ffff88810c697126 by task kworker/u17:0/377
Workqueue: hci0 hci_cmd_sync_work [bluetooth]

Call Trace:
 <TASK>
 dump_stack_lvl+0x66/0xa0
 print_report+0xce/0x5f0
 kasan_report+0xe0/0x110
 conn_update_sync+0x2a/0xf0 [bluetooth]
 hci_cmd_sync_work+0x187/0x210 [bluetooth]
 process_one_work+0x4fd/0xbc0
 worker_thread+0x2d8/0x570
 kthread+0x1ad/0x1f0
 ret_from_fork+0x3c9/0x540
 ret_from_fork_asm+0x1a/0x30

Allocated by task 466:
 hci_conn_params_add+0xa6/0x240 [bluetooth]
 load_conn_param+0x4e1/0x850 [bluetooth]
 hci_sock_sendmsg+0x96b/0xf80 [bluetooth]

Freed by task 474:
 kfree+0x313/0x590
 hci_conn_params_clear_disabled+0x9b/0xc0 [bluetooth]
 load_conn_param+0x4bf/0x850 [bluetooth]
 hci_sock_sendmsg+0x96b/0xf80 [bluetooth]

The Linux kernel CVE team has assigned CVE-2026-68394 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 6.11 with commit 0ece498c27d8cd2fdad6f49a6abc34b8badd8fbc and fixed in 6.12.101 with commit 65ce6fe1b92112ba9064ded932c03180da3dd230
	Issue introduced in 6.11 with commit 0ece498c27d8cd2fdad6f49a6abc34b8badd8fbc and fixed in 6.18.42 with commit 57059ff14d81df4a970b2ea8d8f54431bb91a025
	Issue introduced in 6.11 with commit 0ece498c27d8cd2fdad6f49a6abc34b8badd8fbc and fixed in 7.1.6 with commit b82802b5ab26a7c69fc2e7a0f2baa3c13a6c21aa
	Issue introduced in 6.11 with commit 0ece498c27d8cd2fdad6f49a6abc34b8badd8fbc and fixed in 7.2-rc4 with commit 2bf282f8f715f5d05d6f4c49ffb3bd241c5e667e

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-2026-68394
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/mgmt.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/65ce6fe1b92112ba9064ded932c03180da3dd230
	https://git.kernel.org/stable/c/57059ff14d81df4a970b2ea8d8f54431bb91a025
	https://git.kernel.org/stable/c/b82802b5ab26a7c69fc2e7a0f2baa3c13a6c21aa
	https://git.kernel.org/stable/c/2bf282f8f715f5d05d6f4c49ffb3bd241c5e667e