CVE-2026-52963: ALSA: usb-audio: Bound MIDI endpoint descriptor scans

CVE-2026-52963: ALSA: usb-audio: Bound MIDI endpoint descriptor scans

[Greg Kroah-Hartman]

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

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

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

ALSA: usb-audio: Bound MIDI endpoint descriptor scans

snd_usbmidi_get_ms_info() validates the internal MIDIStreaming endpoint
descriptor size before using baAssocJackID[], but the descriptor walker can
still return a class-specific endpoint descriptor whose bLength exceeds the
remaining bytes in the endpoint-extra scan.

That leaves later flexible-array reads bounded by bLength, but not by the
remaining bytes in the endpoint-extra scan.

Stop walking when bLength is zero or
extends past the remaining endpoint-extra scan.

The Linux kernel CVE team has assigned CVE-2026-52963 to this issue.


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

	Issue introduced in 5.7 with commit 5c6cd7021a05a02fcf37f360592d7c18d4d807fb and fixed in 5.10.258 with commit e2f1260a056eb3215c13c48c5378f3e4112dc3af
	Issue introduced in 5.7 with commit 5c6cd7021a05a02fcf37f360592d7c18d4d807fb and fixed in 5.15.209 with commit c65b137d351e21cbc5630e73ef0eb1e1d75f5b20
	Issue introduced in 5.7 with commit 5c6cd7021a05a02fcf37f360592d7c18d4d807fb and fixed in 6.1.175 with commit 728ab0c72e49ca27185067984cd565425eb69b2e
	Issue introduced in 5.7 with commit 5c6cd7021a05a02fcf37f360592d7c18d4d807fb and fixed in 6.6.141 with commit 3d3b2b01a3e73828e201ece96f863e7a3e0cdc6e
	Issue introduced in 5.7 with commit 5c6cd7021a05a02fcf37f360592d7c18d4d807fb and fixed in 6.12.91 with commit a0226560540c16717efcceaf15c862cf115b01d3
	Issue introduced in 5.7 with commit 5c6cd7021a05a02fcf37f360592d7c18d4d807fb and fixed in 6.18.33 with commit 09141583bd97f4bbd7358e29fd138fe798467cdb
	Issue introduced in 5.7 with commit 5c6cd7021a05a02fcf37f360592d7c18d4d807fb and fixed in 7.0.10 with commit c59159ce10e75b568cd0d4b29efcb0fb0ddecc94
	Issue introduced in 5.7 with commit 5c6cd7021a05a02fcf37f360592d7c18d4d807fb and fixed in 7.1 with commit d6854daa67be623860f4e1873fd3d3c275aba4ed
	Issue introduced in 4.4.238 with commit 9e0c71f2f633b0442661966228827d1a33df485f
	Issue introduced in 4.9.238 with commit 0868bc5654c07628c421547f0821650a8c2cb8f3
	Issue introduced in 4.14.200 with commit 78483c1c7741ffa72991d93d19a75bfdcc2cbf57
	Issue introduced in 4.19.149 with commit 65d95462001c6ccd9bc9499c1fc9a90eca9de496
	Issue introduced in 5.4.69 with commit ca767cf0152d18fc299cde85b18d1f46ac21e1ba

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-2026-52963
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/e2f1260a056eb3215c13c48c5378f3e4112dc3af
	https://git.kernel.org/stable/c/c65b137d351e21cbc5630e73ef0eb1e1d75f5b20
	https://git.kernel.org/stable/c/728ab0c72e49ca27185067984cd565425eb69b2e
	https://git.kernel.org/stable/c/3d3b2b01a3e73828e201ece96f863e7a3e0cdc6e
	https://git.kernel.org/stable/c/a0226560540c16717efcceaf15c862cf115b01d3
	https://git.kernel.org/stable/c/09141583bd97f4bbd7358e29fd138fe798467cdb
	https://git.kernel.org/stable/c/c59159ce10e75b568cd0d4b29efcb0fb0ddecc94
	https://git.kernel.org/stable/c/d6854daa67be623860f4e1873fd3d3c275aba4ed