FKIE_CVE-2026-74682
Vulnerability from fkie_nvd - Published: 2026-08-22 16:16 - Updated: 2026-10-14 13:10
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved:
ALSA: usb-audio: fix OOB write on Type II inbound URBs
data_ep_set_params() sizes each URB transfer buffer before it adds the
Format Type II transfer delimiter:
u->packets = urb_packs;
u->buffer_size = maxsize * u->packets;
if (fmt->fmt_type == UAC_FORMAT_TYPE_II)
u->packets++; /* for transfer delimiter */
u->urb = usb_alloc_urb(u->packets, GFP_KERNEL);
buffer_size is computed from the pre-increment packet count and never
recomputed, so for a Type II endpoint the buffer is one packet short of
the packet count the URB is built with.
prepare_inbound_urb() then lays out one iso frame per packet and never
consults buffer_size:
offs = 0;
for (i = 0; i < urb_ctx->packets; i++) {
urb->iso_frame_desc[i].offset = offs;
urb->iso_frame_desc[i].length = ep->curpacksize;
offs += ep->curpacksize;
}
urb->transfer_buffer_length = offs;
urb->number_of_packets = urb_ctx->packets;
The last descriptor therefore points one packet past the end of the
transfer buffer, where the host controller writes device data on every
inbound transfer. prepare_silent_urb() and prepare_playback_urb() bound
their fill loops by ctx->buffer_size, so only capture is affected.
fmt_type comes from the device's audio streaming descriptors, so any
device advertising a Type II capture format hits this once userspace sets
hw_params on the stream.
KASAN on 7.2.0-rc5 (arm64) with a dummy_hcd/raw-gadget device, one report
per inbound transfer:
BUG: KASAN: slab-out-of-bounds in dummy_timer
Write of size 64 at addr ffff0000186171c0 by task cons02/166
__asan_memcpy
dummy_timer
hrtimer_run_softirq
Allocated by task 166:
usb_alloc_coherent
snd_usb_endpoint_set_params
The buggy address is located 0 bytes to the right of
allocated 64-byte region [ffff000018617180, ffff0000186171c0)
Compute buffer_size after the delimiter packet has been accounted for,
and bound the fill loop by buffer_size, as prepare_silent_urb() already
does on the outbound side. This grows every Type II URB allocation by
one maxsize packet.
Discovered by XBOW, triaged by Baul Lee <baul.lee@xbow.com>
References
Impacted products
| Vendor | Product | Version |
|---|
{
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"sound/usb/endpoint.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "6af5f29af7711233ae68d3b25c15d67478468900",
"status": "affected",
"version": "8fdff6a319e7dac757c558bd283dc4577e68cde7",
"versionType": "git"
},
{
"lessThan": "f1fbb50b99311b35c2e85cc70341d62082dca4b5",
"status": "affected",
"version": "8fdff6a319e7dac757c558bd283dc4577e68cde7",
"versionType": "git"
},
{
"lessThan": "137bf034740e5a2734794908d0aff1e0bd7cee6e",
"status": "affected",
"version": "8fdff6a319e7dac757c558bd283dc4577e68cde7",
"versionType": "git"
},
{
"lessThan": "6607f85242577f33d4540a0d1f4a6137f5367058",
"status": "affected",
"version": "8fdff6a319e7dac757c558bd283dc4577e68cde7",
"versionType": "git"
},
{
"lessThan": "ca22c94bdfc22c564ca2e11c87ba4d17ebeaaa9a",
"status": "affected",
"version": "8fdff6a319e7dac757c558bd283dc4577e68cde7",
"versionType": "git"
},
{
"lessThan": "0a235379825e1a6194e43861ee6658e5fc35686d",
"status": "affected",
"version": "8fdff6a319e7dac757c558bd283dc4577e68cde7",
"versionType": "git"
},
{
"lessThan": "d3ed4e6321bb453757044cb9e5ecb30a33f04903",
"status": "affected",
"version": "8fdff6a319e7dac757c558bd283dc4577e68cde7",
"versionType": "git"
},
{
"lessThan": "69ee44e1a23be62318189dc4b37fa4ad94053269",
"status": "affected",
"version": "8fdff6a319e7dac757c558bd283dc4577e68cde7",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"sound/usb/endpoint.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "3.5"
},
{
"lessThan": "3.5",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.10.*",
"status": "unaffected",
"version": "5.10.265",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.216",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.183",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.152",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.104",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.45",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.9",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: usb-audio: fix OOB write on Type II inbound URBs\n\ndata_ep_set_params() sizes each URB transfer buffer before it adds the\nFormat Type II transfer delimiter:\n\n\tu-\u003epackets = urb_packs;\n\tu-\u003ebuffer_size = maxsize * u-\u003epackets;\n\n\tif (fmt-\u003efmt_type == UAC_FORMAT_TYPE_II)\n\t\tu-\u003epackets++; /* for transfer delimiter */\n\tu-\u003eurb = usb_alloc_urb(u-\u003epackets, GFP_KERNEL);\n\nbuffer_size is computed from the pre-increment packet count and never\nrecomputed, so for a Type II endpoint the buffer is one packet short of\nthe packet count the URB is built with.\n\nprepare_inbound_urb() then lays out one iso frame per packet and never\nconsults buffer_size:\n\n\toffs = 0;\n\tfor (i = 0; i \u003c urb_ctx-\u003epackets; i++) {\n\t\turb-\u003eiso_frame_desc[i].offset = offs;\n\t\turb-\u003eiso_frame_desc[i].length = ep-\u003ecurpacksize;\n\t\toffs += ep-\u003ecurpacksize;\n\t}\n\n\turb-\u003etransfer_buffer_length = offs;\n\turb-\u003enumber_of_packets = urb_ctx-\u003epackets;\n\nThe last descriptor therefore points one packet past the end of the\ntransfer buffer, where the host controller writes device data on every\ninbound transfer. prepare_silent_urb() and prepare_playback_urb() bound\ntheir fill loops by ctx-\u003ebuffer_size, so only capture is affected.\n\nfmt_type comes from the device\u0027s audio streaming descriptors, so any\ndevice advertising a Type II capture format hits this once userspace sets\nhw_params on the stream.\n\nKASAN on 7.2.0-rc5 (arm64) with a dummy_hcd/raw-gadget device, one report\nper inbound transfer:\n\n BUG: KASAN: slab-out-of-bounds in dummy_timer\n Write of size 64 at addr ffff0000186171c0 by task cons02/166\n __asan_memcpy\n dummy_timer\n hrtimer_run_softirq\n Allocated by task 166:\n usb_alloc_coherent\n snd_usb_endpoint_set_params\n The buggy address is located 0 bytes to the right of\n allocated 64-byte region [ffff000018617180, ffff0000186171c0)\n\nCompute buffer_size after the delimiter packet has been accounted for,\nand bound the fill loop by buffer_size, as prepare_silent_urb() already\ndoes on the outbound side. This grows every Type II URB allocation by\none maxsize packet.\n\nDiscovered by XBOW, triaged by Baul Lee \u003cbaul.lee@xbow.com\u003e"
},
{
"lang": "es",
"value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nALSA: usb-audio: corrige escritura fuera de l\u00edmites en URBs entrantes de Tipo II\n\ndata_ep_set_params() dimensiona cada b\u00fafer de transferencia URB antes de a\u00f1adir el delimitador de transferencia de Formato Tipo II:\n\n\tu -\u003e packets = urb_packs;\n\tu -\u003e buffer_size = maxsize * u -\u003e packets;\n\n\tif (fmt -\u003e fmt_type == UAC_FORMAT_TYPE_II)\n\t\tu -\u003e packets++; /* for transfer delimiter */\n\tu -\u003e urb = usb_alloc_urb(u -\u003e packets, GFP_KERNEL);\n\nbuffer_size se calcula a partir del recuento de paquetes previo al incremento y nunca se vuelve a calcular, por lo que para un punto final de Tipo II el b\u00fafer tiene un paquete menos que el recuento de paquetes con el que se construye el URB.\n\nprepare_inbound_urb() luego organiza un marco iso por paquete y nunca consulta buffer_size:\n\n\toffs = 0;\n\tfor (i = 0; i \u003c urb_ctx -\u003e packets; i++) {\n\t\turb -\u003e iso_frame_desc[i].offset = offs;\n\t\turb -\u003e iso_frame_desc[i].length = ep -\u003e curpacksize;\n\t\toffs += ep -\u003e curpacksize;\n\t}\n\n\turb -\u003e transfer_buffer_length = offs;\n\turb -\u003e number_of_packets = urb_ctx -\u003e packets;\n\nEl \u00faltimo descriptor, por lo tanto, apunta un paquete m\u00e1s all\u00e1 del final del b\u00fafer de transferencia, donde el controlador de host escribe datos del dispositivo en cada transferencia entrante. prepare_silent_urb() y prepare_playback_urb() limitan sus bucles de llenado por ctx -\u003e buffer_size, por lo que solo la captura se ve afectada.\n\nfmt_type proviene de los descriptores de transmisi\u00f3n de audio del dispositivo, por lo que cualquier dispositivo que anuncie un formato de captura de Tipo II encuentra esto una vez que el espacio de usuario establece hw_params en el flujo.\n\nKASAN en 7.2.0-rc5 (arm64) con un dispositivo dummy_hcd/raw-gadget, un informe por transferencia entrante:\n\n BUG: KASAN: slab-out-of-bounds in dummy_timer\n Write of size 64 at addr ffff0000186171c0 by task cons02/166\n __asan_memcpy\n dummy_timer\n hrtimer_run_softirq\n Allocated by task 166:\n usb_alloc_coherent\n snd_usb_endpoint_set_params\n The buggy address is located 0 bytes to the right of\n allocated 64-byte region [ffff000018617180, ffff0000186171c0)\n\nCalcule buffer_size despu\u00e9s de que se haya contabilizado el paquete delimitador, y limite el bucle de llenado por buffer_size, como ya hace prepare_silent_urb() en el lado de salida. Esto aumenta cada asignaci\u00f3n de URB de Tipo II en un paquete de tama\u00f1o m\u00e1ximo.\n\nDescubierto por XBOW, clasificado por Baul Lee \u003cbaul.lee@xbow.com\u003e"
}
],
"id": "CVE-2026-74682",
"lastModified": "2026-10-14T13:10:00.187",
"metrics": {},
"published": "2026-08-22T16:16:42.480",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/0a235379825e1a6194e43861ee6658e5fc35686d"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/137bf034740e5a2734794908d0aff1e0bd7cee6e"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/6607f85242577f33d4540a0d1f4a6137f5367058"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/69ee44e1a23be62318189dc4b37fa4ad94053269"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/6af5f29af7711233ae68d3b25c15d67478468900"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/ca22c94bdfc22c564ca2e11c87ba4d17ebeaaa9a"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/d3ed4e6321bb453757044cb9e5ecb30a33f04903"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/f1fbb50b99311b35c2e85cc70341d62082dca4b5"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Received"
}
Loading…
Loading…
Drag nodes to arrange them. Double-click a related vulnerability to open it, or a source to visit its link. The Physics button on the left tunes the layout and the simulation; the legend at the bottom left hides or shows nodes by kind and by sighting type.
Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
Vulnerability timeline
Sightings and recorded dates, grouped by day · UTC
Loading timeline…
Loading…
Loading…
The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
Loading…
Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.