CVE-2026-98565: net: dsa: mt7530: fix NULL dereference on unbind of MT7531 and MT7621

CVE-2026-98565: net: dsa: mt7530: fix NULL dereference on unbind of MT7531 and MT7621

[Greg Kroah-Hartman]

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

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

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

net: dsa: mt7530: fix NULL dereference on unbind of MT7531 and MT7621

The core and io supplies are only requested for ID_MT7530: both the
devm_regulator_get() in probe and the regulator_enable() in
mt7530_setup() are guarded by the switch id, but mt7530_remove()
disables them unconditionally. On an MT7621 or an MT7531 both pointers
are still NULL from devm_kzalloc(), so rmmod or a sysfs unbind calls
regulator_disable() on NULL.

The Linux kernel CVE team has assigned CVE-2026-98565 to this issue.


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

	Issue introduced in 5.1 with commit ddda1ac116c852bb969541ed53cffef7255c4961 and fixed in 6.6.158 with commit bd172580e624bac00d83abd5c4320d2e14d853bc
	Issue introduced in 5.1 with commit ddda1ac116c852bb969541ed53cffef7255c4961 and fixed in 6.12.112 with commit e9a5298532780ecdd05c3220f3e1e3067b3537c3
	Issue introduced in 5.1 with commit ddda1ac116c852bb969541ed53cffef7255c4961 and fixed in 6.18.55 with commit 62c0e38b2e5034184d4502ce77bd178b29e59b83
	Issue introduced in 5.1 with commit ddda1ac116c852bb969541ed53cffef7255c4961 and fixed in 7.2.9 with commit aae2a1f1e3a0ac5eeb439262a2328a2a392413ac
	Issue introduced in 5.1 with commit ddda1ac116c852bb969541ed53cffef7255c4961 and fixed in 7.3-rc5 with commit c2cdef41e0b4d8ed23a5b41e6ad4e64594e055e4

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-2026-98565
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/net/dsa/mt7530-mdio.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/bd172580e624bac00d83abd5c4320d2e14d853bc
	https://git.kernel.org/stable/c/e9a5298532780ecdd05c3220f3e1e3067b3537c3
	https://git.kernel.org/stable/c/62c0e38b2e5034184d4502ce77bd178b29e59b83
	https://git.kernel.org/stable/c/aae2a1f1e3a0ac5eeb439262a2328a2a392413ac
	https://git.kernel.org/stable/c/c2cdef41e0b4d8ed23a5b41e6ad4e64594e055e4