CVE-2026-46288: of: unittest: fix use-after-free in of_unittest_changeset()

CVE-2026-46288: of: unittest: fix use-after-free in of_unittest_changeset()

[Greg Kroah-Hartman]

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

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

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

of: unittest: fix use-after-free in of_unittest_changeset()

The variable 'parent' is assigned the value of 'nchangeset' earlier in the
function, meaning both point to the same struct device_node. The call to
of_node_put(nchangeset) can decrement the reference count to zero and
free the node if there are no other holders. After that, the code still
uses 'parent' to check for the presence of a property and to read a
string property, leading to a use-after-free.

Fix this by moving the of_node_put() call after the last access to
'parent', avoiding the UAF.

The Linux kernel CVE team has assigned CVE-2026-46288 to this issue.


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

	Issue introduced in 6.12 with commit 1c668ea65506e67ce2eae07b69bb09fcdd86e309 and fixed in 6.12.86 with commit 37318d1a27c9cc5a70d3cd7e49e30ec86f2b8ca1
	Issue introduced in 6.12 with commit 1c668ea65506e67ce2eae07b69bb09fcdd86e309 and fixed in 6.18.27 with commit 7f0f0926f3010b10cff5e93446258f971e42f2fd
	Issue introduced in 6.12 with commit 1c668ea65506e67ce2eae07b69bb09fcdd86e309 and fixed in 7.0.4 with commit 6fdad20b7975bdc32e85b45f8f7c640f6687b81f
	Issue introduced in 6.12 with commit 1c668ea65506e67ce2eae07b69bb09fcdd86e309 and fixed in 7.1-rc1 with commit faecdd423c27f0d6090156a435ba9dbbac0eaddb

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-2026-46288
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/of/unittest.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/37318d1a27c9cc5a70d3cd7e49e30ec86f2b8ca1
	https://git.kernel.org/stable/c/7f0f0926f3010b10cff5e93446258f971e42f2fd
	https://git.kernel.org/stable/c/6fdad20b7975bdc32e85b45f8f7c640f6687b81f
	https://git.kernel.org/stable/c/faecdd423c27f0d6090156a435ba9dbbac0eaddb