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CVE PROGRAM SOURCE RECORDUnscored

CVE-2026-74499

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

Description

In the Linux kernel, the following vulnerability has been resolved: ALSA: usb-audio: fix OOB write in snd_usbmidi_akai_output() snd_usbmidi_akai_output() computes its fill-loop bound buf_end = ep->max_transfer - MAX_AKAI_SYSEX_LEN - 1; as a signed int, so a small device-advertised bulk-OUT max_transfer makes buf_end negative. The loop guard then compares the u32 urb->transfer_buffer_length against that negative int: the usual arithmetic conversion turns buf_end into a large unsigned value, so the guard stays true and each iteration keeps appending SysEx framing and payload bytes past the end of the URB transfer buffer, which is only max_transfer bytes long. A USB device that advertises a tiny bulk-OUT endpoint can therefore trigger an attacker-length- and content-controlled heap out-of-bounds write when a process writes to the created /dev/snd/midiC*D* node. Return early when there is no room for even one SysEx, so the loop is never entered with a bound that would wrap. The loop is the last statement of the function, so bailing out is equivalent to it not running. Discovered by XBOW, triaged by Baul Lee <baul.lee@xbow.com>

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • 4434ade8c9334a3ab975d8993de456f06841899e to < 78dfdeb8d2065524ed5928d6470bf3d3244d1009affected
  • 4434ade8c9334a3ab975d8993de456f06841899e to < 00cc659a42ac4e94ec880fae2c9bf22fce69c2e8affected
  • 4434ade8c9334a3ab975d8993de456f06841899e to < ce949d66607cfb000b8d8d84f80f35a886e72683affected
  • 4434ade8c9334a3ab975d8993de456f06841899e to < 29a4c29943631301e85f5e9d10f25741bd78e7baaffected
  • 4434ade8c9334a3ab975d8993de456f06841899e to < 9b22a5c8310b0d55d04f5f0159b913a2fb8b444faffected
  • 4434ade8c9334a3ab975d8993de456f06841899e to < b5305a0d0bb8e90a6fc9f88270d5f6c9b8c40081affected
  • 4434ade8c9334a3ab975d8993de456f06841899e to < 2b7a0f330dd90dd1a7657cec0db019ee1efa4372affected
  • 4434ade8c9334a3ab975d8993de456f06841899e to < 0970274613fb463d376211450cab066d34ebfe6aaffected

Linux Linux

Default version status: affected

  • 2.6.35affected
  • 0 to < 2.6.35unaffected
  • 5.10.265 to ≤ 5.10.*unaffected
  • 5.15.216 to ≤ 5.15.*unaffected
  • 6.1.183 to ≤ 6.1.*unaffected
  • 6.6.151 to ≤ 6.6.*unaffected
  • 6.12.103 to ≤ 6.12.*unaffected
  • 6.18.44 to ≤ 6.18.*unaffected
  • 7.1.8 to ≤ 7.1.*unaffected
  • 7.2 to ≤ *unaffected

References