---
id: CVE-2026-80829
title: 'ALSA: usb-audio: fix OOB write in snd_usbmidi_novation_output()'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

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

  snd_usbmidi_novation_output() lays out a two-byte header at
  transfer_buffer[0..1] and passes &transfer_…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    558fc4485ecc704edfe7876d6cebae4738ff7ef8
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    9c8212436631b0063cb021e9f58df438e3db84d0
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    e9c00d7533f99aa9833c4b598f47e3b3202fdb9a
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    94e4562fcc81badd1d467ddfb88c27e4fae974c2
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    7639ec9755d3ec0ec8cd7c0fdd2c3d3997434870
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    91919b3b99ab7ce3d7dbb39fcf7c6c742a663c0c
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    7f00dbddb51f4f74325cdc7c3f6b19fb3392481a
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    1074c2306901b44ebcb83855583c6776e1e392ea
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    1035a8f63bae28e498b0e7b5ac91d749844a7158
  - Linux 2.6.12
published: '2026-09-04'
updated: '2026-10-19'
sourceUpdated: '2026-10-19T08:44:21.713Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-80829'
references:
  - url: 'https://git.kernel.org/stable/c/558fc4485ecc704edfe7876d6cebae4738ff7ef8'
  - url: 'https://git.kernel.org/stable/c/9c8212436631b0063cb021e9f58df438e3db84d0'
  - url: 'https://git.kernel.org/stable/c/e9c00d7533f99aa9833c4b598f47e3b3202fdb9a'
  - url: 'https://git.kernel.org/stable/c/94e4562fcc81badd1d467ddfb88c27e4fae974c2'
  - url: 'https://git.kernel.org/stable/c/7639ec9755d3ec0ec8cd7c0fdd2c3d3997434870'
  - url: 'https://git.kernel.org/stable/c/91919b3b99ab7ce3d7dbb39fcf7c6c742a663c0c'
  - url: 'https://git.kernel.org/stable/c/7f00dbddb51f4f74325cdc7c3f6b19fb3392481a'
  - url: 'https://git.kernel.org/stable/c/1074c2306901b44ebcb83855583c6776e1e392ea'
  - url: 'https://git.kernel.org/stable/c/1035a8f63bae28e498b0e7b5ac91d749844a7158'
tags:
  - cve.org
epss: 0.00195
epssPercentile: 0.08589
ingestedAt: '2026-10-19T09:16:01.502Z'
---

## Overview

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

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

snd_usbmidi_novation_output() lays out a two-byte header at
transfer_buffer[0..1] and passes &transfer_buffer[2] together with a
length of ep->max_transfer - 2 to snd_rawmidi_transmit():

	count = snd_rawmidi_transmit(ep->ports[0].substream,
				     &transfer_buffer[2],
				     ep->max_transfer - 2);

ep->max_transfer comes from the output endpoint's wMaxPacketSize via
usb_maxpacket(). A malformed or malicious device can advertise a bulk
OUT endpoint with a wMaxPacketSize of 1 - the USB core only clamps this
value downwards - so ep->max_transfer becomes 1 and the count argument
becomes -1.

snd_rawmidi_transmit() passes the negative count on to
__snd_rawmidi_transmit_peek(), where "if (count1 > count) count1 = count"
leaves count1 negative; get_aligned_size() keeps it negative for a
byte-stream substream, so the following memcpy(buffer, ..., count1) runs
with a (size_t)-1 length and writes far past the transfer buffer, which
was allocated with usb_alloc_coherent(ep->max_transfer).

This is the same class of bug that was fixed for snd_usbmidi_akai_output()
in commit 0970274613fb ("ALSA: usb-audio: fix OOB write in
snd_usbmidi_akai_output()"); the novation output routine was left
unguarded. Bail out when the endpoint cannot hold the two-byte header
plus at least one payload byte.

## Affected

- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 558fc4485ecc704edfe7876d6cebae4738ff7ef8`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 9c8212436631b0063cb021e9f58df438e3db84d0`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < e9c00d7533f99aa9833c4b598f47e3b3202fdb9a`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 94e4562fcc81badd1d467ddfb88c27e4fae974c2`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 7639ec9755d3ec0ec8cd7c0fdd2c3d3997434870`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 91919b3b99ab7ce3d7dbb39fcf7c6c742a663c0c`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 7f00dbddb51f4f74325cdc7c3f6b19fb3392481a`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 1074c2306901b44ebcb83855583c6776e1e392ea`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 1035a8f63bae28e498b0e7b5ac91d749844a7158`
- `Linux 2.6.12`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.