CVE-2026-74536: Bluetooth: ISO: fix leaking sk after socket release

CVE-2026-74536: Bluetooth: ISO: fix leaking sk after socket release

[Greg Kroah-Hartman]

From: Greg Kroah-Hartman <gregkh@kernel.org>

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

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

Bluetooth: ISO: fix leaking sk after socket release

iso_sock_kill() tests !sock_flag(sk, SOCK_ZAPPED) || sk->sk_socket ||
sock_flag(sk, SOCK_DEAD) for early return, but this is always true since
sock_orphan(sk) sets SOCK_DEAD, so the sk reference released by socket
always leaks, iso_sock_destruct is never called.

The socket reference also leaks when __iso_sock_close() does not set
SOCK_ZAPPED, since iso_conn_del() does not call iso_sock_kill() after
zapping.

Fix by replacing SOCK_DEAD by BT_SK_KILLED flag that is not used for
something else, and lock_sock to ensure iso_sock_kill() puts sk only
after socket release only once. Release and iso_conn_del may run
concurrently. Call iso_sock_kill() from iso_conn_del() to clean sk up
after zapping.

Remove call to iso_sock_kill() from iso_sock_close(), as it's generally
no-op there.

The Linux kernel CVE team has assigned CVE-2026-74536 to this issue.


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

	Issue introduced in 6.0 with commit ccf74f2390d60a2f9a75ef496d2564abb478f46a and fixed in 6.12.103 with commit 96ed3c772c08e7a91c399567f412618e43231023
	Issue introduced in 6.0 with commit ccf74f2390d60a2f9a75ef496d2564abb478f46a and fixed in 6.18.44 with commit e76a0ae6542ae43241b2147bacf4990e7ae5316a
	Issue introduced in 6.0 with commit ccf74f2390d60a2f9a75ef496d2564abb478f46a and fixed in 7.1.8 with commit e30e5ca63c8fbe3cd505fbb419bb547760cda633
	Issue introduced in 6.0 with commit ccf74f2390d60a2f9a75ef496d2564abb478f46a and fixed in 7.2-rc6 with commit ce57442a379212fe3fda59c9437ee8217eceb5b1

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-2026-74536
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/iso.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/96ed3c772c08e7a91c399567f412618e43231023
	https://git.kernel.org/stable/c/e76a0ae6542ae43241b2147bacf4990e7ae5316a
	https://git.kernel.org/stable/c/e30e5ca63c8fbe3cd505fbb419bb547760cda633
	https://git.kernel.org/stable/c/ce57442a379212fe3fda59c9437ee8217eceb5b1