CVE-2026-68195: wifi: mt76: mt7615: drop TXRX_NOTIFY on non-mmio buses

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

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

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

wifi: mt76: mt7615: drop TXRX_NOTIFY on non-mmio buses

PKT_TYPE_TXRX_NOTIFY is an mmio-only event, but mt7615_rx_check() and
mt7615_queue_rx_skb() dispatch it to mt7615_mac_tx_free() on every bus.
mt7615_mac_tx_free() cleans the DMA tx queues with
mt76_queue_tx_cleanup(), which calls queue_ops->tx_cleanup(). Only the
mmio queue ops implement that callback; on the mt7663 USB and SDIO
buses it is NULL, so a TXRX_NOTIFY there calls a NULL pointer in the RX
worker. Same defect as the mt7921 and mt7925 patches in this series.

Drop the event on non-mmio buses via mt76_is_mmio(), as in
commit 5683e1488aa9 ("wifi: mt76: connac: do not check WED status for
non-mmio devices").

The Linux kernel CVE team has assigned CVE-2026-68195 to this issue.


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

	Issue introduced in 5.8 with commit eb99cc95c3b6513b495c4839ac4917206705f657 and fixed in 6.6.148 with commit f2a72f47c5fb4ba6887e85bbe809d7e5b318d9d5
	Issue introduced in 5.8 with commit eb99cc95c3b6513b495c4839ac4917206705f657 and fixed in 6.12.101 with commit 88c98ef247a3126fea9bbbda953a18a2f36c3ea7
	Issue introduced in 5.8 with commit eb99cc95c3b6513b495c4839ac4917206705f657 and fixed in 6.18.42 with commit ab4d213393e846baa6437497f94dda7553cbeda7
	Issue introduced in 5.8 with commit eb99cc95c3b6513b495c4839ac4917206705f657 and fixed in 7.1.6 with commit b2ab73b8123ce6cf2bc32634bfee4928676ffa66
	Issue introduced in 5.8 with commit eb99cc95c3b6513b495c4839ac4917206705f657 and fixed in 7.2-rc5 with commit 39afc46c0243d10b7795e6e6cf4ae91f41732120

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-2026-68195
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/mt7615/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/f2a72f47c5fb4ba6887e85bbe809d7e5b318d9d5
	https://git.kernel.org/stable/c/88c98ef247a3126fea9bbbda953a18a2f36c3ea7
	https://git.kernel.org/stable/c/ab4d213393e846baa6437497f94dda7553cbeda7
	https://git.kernel.org/stable/c/b2ab73b8123ce6cf2bc32634bfee4928676ffa66
	https://git.kernel.org/stable/c/39afc46c0243d10b7795e6e6cf4ae91f41732120