CVE-2026-68423: mtd: virt_concat: fix use-after-free in mtd_virt_concat_destroy()

CVE-2026-68423: mtd: virt_concat: fix use-after-free in mtd_virt_concat_destroy()

[Greg Kroah-Hartman]

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

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

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

mtd: virt_concat: fix use-after-free in mtd_virt_concat_destroy()

mtd_concat_destroy() frees item->concat so calling
mtd_virt_concat_put_mtd_devices(item->concat) after that leads to a
use-after-free.

Fix it by moving mtd_virt_concat_put_mtd_devices() before
mtd_concat_destroy().

The Linux kernel CVE team has assigned CVE-2026-68423 to this issue.


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

	Issue introduced in 7.1 with commit 43db6366fc2de02050e66389f5628d3fdc9af10a and fixed in 7.1.6 with commit d36520e5da8bf87265b334def0daaadf3603cc62
	Issue introduced in 7.1 with commit 43db6366fc2de02050e66389f5628d3fdc9af10a and fixed in 7.2-rc4 with commit 4b45d7836b9526b8776af5f29219615be9417230

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-2026-68423
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/mtd/mtd_virt_concat.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/d36520e5da8bf87265b334def0daaadf3603cc62
	https://git.kernel.org/stable/c/4b45d7836b9526b8776af5f29219615be9417230