CVE-2026-98836
In the Linux kernel, the following vulnerability has been resolved:
ALSA: line6: reject oversized playback packets
Each playback URB is handed a slice of out.buffer that is exactly LINE6_ISO_PACKETS * max_packet_size_out bytes, sized from the OUT endpoint, but the number of bytes written into that slice is never compared against it.
submit_audio_out_urb() takes the frame count from prev_fsize, which audio_in_callback() derived from the *IN* endpoint's received packet length, and rescales it with the playback frame size; when prev_fsize is still zero it synthesizes a length from the sample rate instead.
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On a device declaring a large IN wMaxPacketSize and a small OUT wMaxPacketSize, the resulting memcpy(), or the memset() when the playback stream is idle, runs past its slice and, as the reproducer below shows, beyond the allocation.
usb_submit_urb() is not a backstop. max_packet_size_out comes from usb_maxpacket(), which returns only the low 11 bits of wMaxPacketSize, while USB core validates a high-speed isochronous length against that base scaled by usb_endpoint_maxp_mult(). A length of up to three times the allocated slice is therefore accepted, and even a rejected URB is only rejected after the write.
Reject a packet that does not fit the slice the driver allocated for it. Clamping it instead would silently shorten the capture-derived rate feedback and desynchronize the two streams.
Technical details traces, logs and code from the original report
BUG: KASAN: slab-out-of-bounds in submit_audio_out_urb (sound/usb/line6/playback.c:229) Write of size 1024 at addr ffff888100bbd400 by task kworker/1:2/5002 Workqueue: events line6_startup_work Call Trace: __asan_memcpy (mm/kasan/shadow.c:106) submit_audio_out_urb (sound/usb/line6/playback.c:229) line6_submit_audio_out_all_urbs (sound/usb/line6/playback.c:291) line6_stream_start (sound/usb/line6/pcm.c:194) line6_pcm_acquire (sound/usb/line6/pcm.c:337) line6_startup_work (sound/usb/line6/driver.c:728) process_one_work (kernel/workqueue.c:3396) worker_thread (kernel/workqueue.c:3479 kernel/workqueue.c:3560) kthread (kernel/kthread.c:436) ret_from_fork (arch/x86/kernel/process.c:158) ret_from_fork_asm (arch/x86/entry/entry_64.S:245) The buggy address belongs to the object at ffff888100bbd400 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 0 bytes inside of allocated 256-byte region [ffff888100bbd400, ffff888100bbd500)
CVSS
NVD hasn't assigned a CVSS score to this CVE (common since the April 2026 policy change).
Exploitation probability (EPSS)
- Probability of exploitation in the next 30 days
- 0.17 %
- Percentile among all scored CVEs
- 6
- Score date
- 10/20/2026
EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).
Affected technologies (1)
⚠ AI-inferred from the description — NVD hasn't analyzed this CVE yet, these aren't verified CPEs.
References
Show 4 references
Raw JSON (NVD)
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{
"id": "CVE-2026-98836",
"cveTags": [],
"metrics": {},
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "7a0f55aeeb8f1fa32a119d34ddfefc6100936692",
"lessThan": "a84371be89c39ccc46c7af8b9eb15c448df9265f",
"versionType": "git"
},
{
"status": "affected",
"version": "7a0f55aeeb8f1fa32a119d34ddfefc6100936692",
"lessThan": "3f75da1e4ee699f6650d23d6897cf443b01856c7",
"versionType": "git"
},
{
"status": "affected",
"version": "7a0f55aeeb8f1fa32a119d34ddfefc6100936692",
"lessThan": "b78748424f29f07d310484b2b36afdececa74389",
"versionType": "git"
},
{
"status": "affected",
"version": "7a0f55aeeb8f1fa32a119d34ddfefc6100936692",
"lessThan": "61b0a5a114fa4552892da5c0ff2f42e63bf08c6b",
"versionType": "git"
}
],
"programFiles": [
"sound/usb/line6/playback.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "4.9"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "4.9",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.12.113",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.56",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.2.10",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"sound/usb/line6/playback.c"
],
"defaultStatus": "affected"
}
]
}
],
"published": "2026-10-18T16:17:37.830",
"references": [
{
"url": "https://git.kernel.org/stable/c/3f75da1e4ee699f6650d23d6897cf443b01856c7",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/61b0a5a114fa4552892da5c0ff2f42e63bf08c6b",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/a84371be89c39ccc46c7af8b9eb15c448df9265f",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/b78748424f29f07d310484b2b36afdececa74389",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"vulnStatus": "Received",
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: line6: reject oversized playback packets\n\nEach playback URB is handed a slice of out.buffer that is exactly\nLINE6_ISO_PACKETS * max_packet_size_out bytes, sized from the OUT\nendpoint, but the number of bytes written into that slice is never\ncompared against it.\n\nsubmit_audio_out_urb() takes the frame count from prev_fsize, which\naudio_in_callback() derived from the *IN* endpoint's received packet\nlength, and rescales it with the playback frame size; when prev_fsize is\nstill zero it synthesizes a length from the sample rate instead. On a\ndevice declaring a large IN wMaxPacketSize and a small OUT\nwMaxPacketSize, the resulting memcpy(), or the memset() when the\nplayback stream is idle, runs past its slice and, as the reproducer\nbelow shows, beyond the allocation.\n\nusb_submit_urb() is not a backstop. max_packet_size_out comes from\nusb_maxpacket(), which returns only the low 11 bits of wMaxPacketSize,\nwhile USB core validates a high-speed isochronous length against that\nbase scaled by usb_endpoint_maxp_mult(). A length of up to three times\nthe allocated slice is therefore accepted, and even a rejected URB is\nonly rejected after the write.\n\nReject a packet that does not fit the slice the driver allocated for it.\nClamping it instead would silently shorten the capture-derived rate\nfeedback and desynchronize the two streams.\n\n BUG: KASAN: slab-out-of-bounds in submit_audio_out_urb (sound/usb/line6/playback.c:229)\n Write of size 1024 at addr ffff888100bbd400 by task kworker/1:2/5002\n Workqueue: events line6_startup_work\n Call Trace:\n __asan_memcpy (mm/kasan/shadow.c:106)\n submit_audio_out_urb (sound/usb/line6/playback.c:229)\n line6_submit_audio_out_all_urbs (sound/usb/line6/playback.c:291)\n line6_stream_start (sound/usb/line6/pcm.c:194)\n line6_pcm_acquire (sound/usb/line6/pcm.c:337)\n line6_startup_work (sound/usb/line6/driver.c:728)\n process_one_work (kernel/workqueue.c:3396)\n worker_thread (kernel/workqueue.c:3479 kernel/workqueue.c:3560)\n kthread (kernel/kthread.c:436)\n ret_from_fork (arch/x86/kernel/process.c:158)\n ret_from_fork_asm (arch/x86/entry/entry_64.S:245)\n\n The buggy address belongs to the object at ffff888100bbd400\n which belongs to the cache kmalloc-256 of size 256\n The buggy address is located 0 bytes inside of\n allocated 256-byte region [ffff888100bbd400, ffff888100bbd500)"
}
],
"lastModified": "2026-10-19T10:19:47.630",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}