CVE-2026-64220: device property: set fwnode->secondary to NULL in fwnode_init()

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

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

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

device property: set fwnode->secondary to NULL in fwnode_init()

If a firmware node is allocated on the stack (for instance: temporary
software node whose life-time we control) or on the heap - but using a
non-zeroing allocation function - and initialized using fwnode_init(),
its secondary pointer will contain uninitalized memory which likely will
be neither NULL nor IS_ERR() and so may end up being dereferenced (for
example: in dev_to_swnode()). Set fwnode->secondary to NULL on
initialization.

The Linux kernel CVE team has assigned CVE-2026-64220 to this issue.


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

	Issue introduced in 5.11 with commit 01bb86b380a306bd937c96da36f66429f3362137 and fixed in 5.15.209 with commit f0e211d6539fae800217c10797993b7592d6ab01
	Issue introduced in 5.11 with commit 01bb86b380a306bd937c96da36f66429f3362137 and fixed in 6.1.175 with commit 3f1024deeab3b5443c29b3de4fe475e87309b8fa
	Issue introduced in 5.11 with commit 01bb86b380a306bd937c96da36f66429f3362137 and fixed in 6.6.142 with commit 371f53925a6714d0aa35f1aefdffc3e8cd62f480
	Issue introduced in 5.11 with commit 01bb86b380a306bd937c96da36f66429f3362137 and fixed in 6.12.92 with commit 34bf74b1fd2e4a44e27821a329204caf09df2976
	Issue introduced in 5.11 with commit 01bb86b380a306bd937c96da36f66429f3362137 and fixed in 6.18.34 with commit 508fd8ab158abd04b7f7d0f707cd6d6c405df4ea
	Issue introduced in 5.11 with commit 01bb86b380a306bd937c96da36f66429f3362137 and fixed in 7.0.11 with commit f59e686c778cb41b8f7aa8fab2afd6a01afb3d47
	Issue introduced in 5.11 with commit 01bb86b380a306bd937c96da36f66429f3362137 and fixed in 7.1 with commit 215c90ee656114f5e8c32408228d97082f8e0eef

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-2026-64220
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:
	include/linux/fwnode.h


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/f0e211d6539fae800217c10797993b7592d6ab01
	https://git.kernel.org/stable/c/3f1024deeab3b5443c29b3de4fe475e87309b8fa
	https://git.kernel.org/stable/c/371f53925a6714d0aa35f1aefdffc3e8cd62f480
	https://git.kernel.org/stable/c/34bf74b1fd2e4a44e27821a329204caf09df2976
	https://git.kernel.org/stable/c/508fd8ab158abd04b7f7d0f707cd6d6c405df4ea
	https://git.kernel.org/stable/c/f59e686c778cb41b8f7aa8fab2afd6a01afb3d47
	https://git.kernel.org/stable/c/215c90ee656114f5e8c32408228d97082f8e0eef