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

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-74499
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-15 13:17:54 UTC
Updated2026-08-19 17:21:07 UTC
DescriptionIn 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 <[email protected]>

Risk And Classification

EPSS: 0.001680000 probability, percentile 0.065330000 (date 2026-08-19)

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 4434ade8c9334a3ab975d8993de456f06841899e 78dfdeb8d2065524ed5928d6470bf3d3244d1009 git Not specified
CNA Linux Linux affected 4434ade8c9334a3ab975d8993de456f06841899e 00cc659a42ac4e94ec880fae2c9bf22fce69c2e8 git Not specified
CNA Linux Linux affected 4434ade8c9334a3ab975d8993de456f06841899e ce949d66607cfb000b8d8d84f80f35a886e72683 git Not specified
CNA Linux Linux affected 4434ade8c9334a3ab975d8993de456f06841899e 29a4c29943631301e85f5e9d10f25741bd78e7ba git Not specified
CNA Linux Linux affected 4434ade8c9334a3ab975d8993de456f06841899e 9b22a5c8310b0d55d04f5f0159b913a2fb8b444f git Not specified
CNA Linux Linux affected 4434ade8c9334a3ab975d8993de456f06841899e b5305a0d0bb8e90a6fc9f88270d5f6c9b8c40081 git Not specified
CNA Linux Linux affected 4434ade8c9334a3ab975d8993de456f06841899e 2b7a0f330dd90dd1a7657cec0db019ee1efa4372 git Not specified
CNA Linux Linux affected 4434ade8c9334a3ab975d8993de456f06841899e 0970274613fb463d376211450cab066d34ebfe6a git Not specified
CNA Linux Linux affected 2.6.35 Not specified
CNA Linux Linux unaffected 2.6.35 semver Not specified
CNA Linux Linux unaffected 5.10.265 5.10.* semver Not specified
CNA Linux Linux unaffected 5.15.216 5.15.* semver Not specified
CNA Linux Linux unaffected 6.1.183 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.151 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.103 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.44 6.18.* semver Not specified
CNA Linux Linux unaffected 7.1.8 7.1.* semver Not specified
CNA Linux Linux unaffected 7.2 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/78dfdeb8d2065524ed5928d6470bf3d3244d1009 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/29a4c29943631301e85f5e9d10f25741bd78e7ba 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/00cc659a42ac4e94ec880fae2c9bf22fce69c2e8 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/ce949d66607cfb000b8d8d84f80f35a886e72683 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/9b22a5c8310b0d55d04f5f0159b913a2fb8b444f 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/2b7a0f330dd90dd1a7657cec0db019ee1efa4372 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/b5305a0d0bb8e90a6fc9f88270d5f6c9b8c40081 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/0970274613fb463d376211450cab066d34ebfe6a 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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