CVE-2026-74499
Full vulnerability record from the local CVENow database.
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 <[email protected]>
Severity
Not scored
CVSS score
Not available
Vulnerability status
Received
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2026-08-15 13:17:54.863000
Last modified
2026-11-06 17:19:49.930000
View original CVE JSON
{
"id": "CVE-2026-74499",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"published": "2026-08-15T13:17:54.863",
"lastModified": "2026-11-06T17:19:49.930",
"vulnStatus": "Received",
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: usb-audio: fix OOB write in snd_usbmidi_akai_output()\n\nsnd_usbmidi_akai_output() computes its fill-loop bound\n\n\tbuf_end = ep->max_transfer - MAX_AKAI_SYSEX_LEN - 1;\n\nas a signed int, so a small device-advertised bulk-OUT max_transfer\nmakes buf_end negative. The loop guard then compares the u32\nurb->transfer_buffer_length against that negative int: the usual\narithmetic conversion turns buf_end into a large unsigned value, so the\nguard stays true and each iteration keeps appending SysEx framing and\npayload bytes past the end of the URB transfer buffer, which is only\nmax_transfer bytes long.\n\nA USB device that advertises a tiny bulk-OUT endpoint can therefore\ntrigger an attacker-length- and content-controlled heap out-of-bounds\nwrite when a process writes to the created /dev/snd/midiC*D* node.\n\nReturn early when there is no room for even one SysEx, so the loop is\nnever entered with a bound that would wrap. The loop is the last\nstatement of the function, so bailing out is equivalent to it not\nrunning.\n\nDiscovered by XBOW, triaged by Baul Lee <[email protected]>"
}
],
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "unaffected",
"programFiles": [
"sound/usb/midi.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"versions": [
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{
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"lessThanOrEqual": "5.10.*",
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"status": "unaffected"
},
{
"version": "5.15.216",
"lessThanOrEqual": "5.15.*",
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"status": "unaffected"
},
{
"version": "6.1.183",
"lessThanOrEqual": "6.1.*",
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"status": "unaffected"
},
{
"version": "6.6.151",
"lessThanOrEqual": "6.6.*",
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"status": "unaffected"
},
{
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"versionType": "original_commit_for_fix",
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}
],
"metrics": {
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"timestamp": "2026-11-06T16:58:49.686471Z",
"id": "CVE-2026-74499",
"options": [
{
"exploitation": "none"
},
{
"automatable": "no"
},
{
"technicalImpact": "partial"
}
],
"role": "CISA Coordinator",
"version": "2.0.3"
}
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"references": [
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