linux-cve-announce - CVE-2026-23221: bus: fsl-mc: fix use-after-free in driver_override

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Message-ID: <2026021806-CVE-2026-23221-43ae@gregkh>
Date: Wed, 18 Feb 2026 15:54:10 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2026-23221: bus: fsl-mc: fix use-after-free in driver_override_show()

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

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

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

bus: fsl-mc: fix use-after-free in driver_override_show()

The driver_override_show() function reads the driver_override string
without holding the device_lock. However, driver_override_store() uses
driver_set_override(), which modifies and frees the string while holding
the device_lock.

This can result in a concurrent use-after-free if the string is freed
by the store function while being read by the show function.

Fix this by holding the device_lock around the read operation.

The Linux kernel CVE team has assigned CVE-2026-23221 to this issue.


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

	Fixed in 6.18.11 with commit 1d6bd6183e723a7b256ff34bbb5b498b5f4f2ec0
	Fixed in 6.19.1 with commit a2ae33e1c6361e960a4d00f7cf75d880b54f9528

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-2026-23221
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:
	drivers/bus/fsl-mc/fsl-mc-bus.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/1d6bd6183e723a7b256ff34bbb5b498b5f4f2ec0
	https://git.kernel.org/stable/c/a2ae33e1c6361e960a4d00f7cf75d880b54f9528
	https://git.kernel.org/stable/c/148891e95014b5dc5878acefa57f1940c281c431