CVE-2026-74531: Bluetooth: hci_conn: hold conn reference in abort_conn_sync()

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

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

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

Bluetooth: hci_conn: hold conn reference in abort_conn_sync()

There is theoretical UAF if the conn is freed while the hci_sync task is
running.

Hold refcount to avoid that.

The Linux kernel CVE team has assigned CVE-2026-74531 to this issue.


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

	Issue introduced in 6.6.51 with commit 249c88e7fb45b6b705040c5af4bd0d0f2bc9735c and fixed in 6.6.151 with commit 64d1645f26aa49b5a86ba2fccd0bb6749ea725a6
	Issue introduced in 6.11 with commit 227a0cdf4a028a73dc256d0f5144b4808d718893 and fixed in 6.12.103 with commit 963fb4b8e7d1ab07b4ae45bf15d41e667c88caca
	Issue introduced in 6.11 with commit 227a0cdf4a028a73dc256d0f5144b4808d718893 and fixed in 6.18.44 with commit e8f9fef362bab431d95371d3406bc720350290c3
	Issue introduced in 6.11 with commit 227a0cdf4a028a73dc256d0f5144b4808d718893 and fixed in 7.1.8 with commit fa812cfa81aa3d4a7b6ce8277979af57b3f79712
	Issue introduced in 6.11 with commit 227a0cdf4a028a73dc256d0f5144b4808d718893 and fixed in 7.2-rc6 with commit 5761d003daa987ac81463f570713ce9c9dd204e5
	Issue introduced in 6.10.10 with commit 58afdc9b18871eb1d461c725be9e9f3f44a39aeb

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-2026-74531
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/hci_conn.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/64d1645f26aa49b5a86ba2fccd0bb6749ea725a6
	https://git.kernel.org/stable/c/963fb4b8e7d1ab07b4ae45bf15d41e667c88caca
	https://git.kernel.org/stable/c/e8f9fef362bab431d95371d3406bc720350290c3
	https://git.kernel.org/stable/c/fa812cfa81aa3d4a7b6ce8277979af57b3f79712
	https://git.kernel.org/stable/c/5761d003daa987ac81463f570713ce9c9dd204e5