CVE-2026-74497: ALSA: usb-audio: Clamp frame size in implicit-feedback mode

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

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

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

ALSA: usb-audio: Clamp frame size in implicit-feedback mode

snd_usb_handle_sync_urb() scales received sync packet sizes by the sender's
stride and stores the result directly in out_packet->packet_size[i]. If a
connected USB device sends an oversized sync packet, this frame count can
exceed ep->maxframesize.

The un-clamped frame count then propagates to the playback endpoint queue,
potentially driving packet transfers beyond the endpoint's hardware frame
limits.

Cap the calculated frame count against ep->maxframesize in
snd_usb_handle_sync_urb() to prevent oversized packets from entering the
playback queue.

The Linux kernel CVE team has assigned CVE-2026-74497 to this issue.


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

	Issue introduced in 3.8 with commit 28acb12014fb0c3e1edfdab1b1e3e266cf651550 and fixed in 6.6.151 with commit 56ac3e7c90f6b45969c3fd07a98fad760ffd6901
	Issue introduced in 3.8 with commit 28acb12014fb0c3e1edfdab1b1e3e266cf651550 and fixed in 6.12.103 with commit be97fea7451d758881b95af78e900dd0d58a382a
	Issue introduced in 3.8 with commit 28acb12014fb0c3e1edfdab1b1e3e266cf651550 and fixed in 6.18.44 with commit 2db4535d6af79276a64449201c5be5feffb31c64
	Issue introduced in 3.8 with commit 28acb12014fb0c3e1edfdab1b1e3e266cf651550 and fixed in 7.1.8 with commit 53f0aa37eb945f3c983f61d12fc35eb33debb8a9
	Issue introduced in 3.8 with commit 28acb12014fb0c3e1edfdab1b1e3e266cf651550 and fixed in 7.2-rc6 with commit 8d7a30c50c2e58a6839634ed0acde14466d1dc61

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-2026-74497
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/endpoint.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/56ac3e7c90f6b45969c3fd07a98fad760ffd6901
	https://git.kernel.org/stable/c/be97fea7451d758881b95af78e900dd0d58a382a
	https://git.kernel.org/stable/c/2db4535d6af79276a64449201c5be5feffb31c64
	https://git.kernel.org/stable/c/53f0aa37eb945f3c983f61d12fc35eb33debb8a9
	https://git.kernel.org/stable/c/8d7a30c50c2e58a6839634ed0acde14466d1dc61