CVE-2026-90033: ALSA: usb-audio: fix OOB write in snd_usbmidi_us122l_output()

CVE-2026-90033: ALSA: usb-audio: fix OOB write in snd_usbmidi_us122l_output()

[Greg Kroah-Hartman]

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

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

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

ALSA: usb-audio: fix OOB write in snd_usbmidi_us122l_output()

The snd_usbmidi_us122l_output() picks a count of 2 on anything slower
than high speed and never relates it to ep->max_transfer.  The URB
buffer holds exactly max_transfer bytes, so a device declaring a one
byte bulk endpoint takes two bytes from snd_rawmidi_transmit(), and the
memset that pads the rest computes 1 - 2 in int and wraps to SIZE_MAX.

Only 0x800e and 0x800f are pinned to nine bytes.  The US-122MKII at
0x0644:0x8021 falls to the default and takes usb_maxpacket(), which the
USB core only clamps downward.

The akai and novation output ops in this file were given the same guard
recently.  Do the same here.

The Linux kernel CVE team has assigned CVE-2026-90033 to this issue.


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

	Issue introduced in 2.6.28 with commit 030a07e441296c372f946cd4065b5d831d8dc40c and fixed in 5.10.270 with commit 5538daf2a5cc80ac3f3e913c0db045d92d995d40
	Issue introduced in 2.6.28 with commit 030a07e441296c372f946cd4065b5d831d8dc40c and fixed in 5.15.221 with commit a441a8e52148c91c2f2a91f42e3b9bc961a13a4b
	Issue introduced in 2.6.28 with commit 030a07e441296c372f946cd4065b5d831d8dc40c and fixed in 6.1.188 with commit 2dae0e3a59e31f78222279d544b98e747cd1fbff
	Issue introduced in 2.6.28 with commit 030a07e441296c372f946cd4065b5d831d8dc40c and fixed in 6.6.157 with commit 1d4add2b832b56f81bb0eab065ec35c610343018
	Issue introduced in 2.6.28 with commit 030a07e441296c372f946cd4065b5d831d8dc40c and fixed in 6.12.110 with commit de6d252f115be887a701c09a05cdb076f3a590c9
	Issue introduced in 2.6.28 with commit 030a07e441296c372f946cd4065b5d831d8dc40c and fixed in 6.18.51 with commit 9392a2c346762ffee8edd1ba8bac50d2e24a2ed7
	Issue introduced in 2.6.28 with commit 030a07e441296c372f946cd4065b5d831d8dc40c and fixed in 7.2.5 with commit 9d81885d97cba7796d1f8edc88f2499c8296f5b9
	Issue introduced in 2.6.28 with commit 030a07e441296c372f946cd4065b5d831d8dc40c and fixed in 7.3-rc2 with commit e4637ce34607f1733a34a57294966d26b263e626

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-2026-90033
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:
	sound/usb/midi.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/5538daf2a5cc80ac3f3e913c0db045d92d995d40
	https://git.kernel.org/stable/c/a441a8e52148c91c2f2a91f42e3b9bc961a13a4b
	https://git.kernel.org/stable/c/2dae0e3a59e31f78222279d544b98e747cd1fbff
	https://git.kernel.org/stable/c/1d4add2b832b56f81bb0eab065ec35c610343018
	https://git.kernel.org/stable/c/de6d252f115be887a701c09a05cdb076f3a590c9
	https://git.kernel.org/stable/c/9392a2c346762ffee8edd1ba8bac50d2e24a2ed7
	https://git.kernel.org/stable/c/9d81885d97cba7796d1f8edc88f2499c8296f5b9
	https://git.kernel.org/stable/c/e4637ce34607f1733a34a57294966d26b263e626