CVE-2026-90374: wifi: mt76: mt7996: validate RX band_idx before dereferencing phys[]

CVE-2026-90374: wifi: mt76: mt7996: validate RX band_idx before dereferencing phys[]

[Greg Kroah-Hartman]

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

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

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

wifi: mt76: mt7996: validate RX band_idx before dereferencing phys[]

band_idx comes from a 2-bit descriptor field (0-3) and was used directly
to index dev->mt76.phys[] (size __MT_MAX_BAND == 3) and dereference the
result. A corrupt or reserved descriptor value could index out of bounds
or hit a NULL phy on parts with fewer bands. Reject invalid band indices,
mirroring mt7996_rx_get_wcid().

The Linux kernel CVE team has assigned CVE-2026-90374 to this issue.


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

	Issue introduced in 6.2 with commit 98686cd21624c75a043e96812beadddf4f6f48e5 and fixed in 6.12.110 with commit 535091c587268cc783608642838a655d828eefdd
	Issue introduced in 6.2 with commit 98686cd21624c75a043e96812beadddf4f6f48e5 and fixed in 6.18.52 with commit 0f53ece876e1f3bbb3e18f48afc4af1ee967b16c
	Issue introduced in 6.2 with commit 98686cd21624c75a043e96812beadddf4f6f48e5 and fixed in 7.2.6 with commit b1c5cf8903bec5476a2233b4e45287b9a2213e02
	Issue introduced in 6.2 with commit 98686cd21624c75a043e96812beadddf4f6f48e5 and fixed in 7.3-rc1 with commit 2243778a5fae8329ab5f18e7adcd7e03b911a1b7

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-2026-90374
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/wireless/mediatek/mt76/mt7996/mac.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/535091c587268cc783608642838a655d828eefdd
	https://git.kernel.org/stable/c/0f53ece876e1f3bbb3e18f48afc4af1ee967b16c
	https://git.kernel.org/stable/c/b1c5cf8903bec5476a2233b4e45287b9a2213e02
	https://git.kernel.org/stable/c/2243778a5fae8329ab5f18e7adcd7e03b911a1b7