CVE-2026-74682
Estado: RecibidaSin puntuar—
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:
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:
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.
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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.
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>
Detalles técnicos trazas, registros y código del informe original
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);
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;
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)CVSS
NVD no ha asignado puntuación CVSS a esta CVE (habitual desde el cambio de política de abril de 2026).
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.22%
- Percentil entre todas las CVEs puntuadas: 11
- Fecha de la puntuación: 5/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
Tecnologías afectadas (1)
⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.
Referencias
- https://git.kernel.org/stable/c/0a235379825e1a6194e43861ee6658e5fc35686d
- https://git.kernel.org/stable/c/137bf034740e5a2734794908d0aff1e0bd7cee6e
- https://git.kernel.org/stable/c/6607f85242577f33d4540a0d1f4a6137f5367058
- https://git.kernel.org/stable/c/69ee44e1a23be62318189dc4b37fa4ad94053269
- https://git.kernel.org/stable/c/6af5f29af7711233ae68d3b25c15d67478468900
- https://git.kernel.org/stable/c/ca22c94bdfc22c564ca2e11c87ba4d17ebeaaa9a
- https://git.kernel.org/stable/c/d3ed4e6321bb453757044cb9e5ecb30a33f04903
- https://git.kernel.org/stable/c/f1fbb50b99311b35c2e85cc70341d62082dca4b5
JSON original (NVD)
Mostrar
{
"id": "CVE-2026-74682",
"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": "8fdff6a319e7dac757c558bd283dc4577e68cde7",
"lessThan": "6af5f29af7711233ae68d3b25c15d67478468900",
"versionType": "git"
},
{
"status": "affected",
"version": "8fdff6a319e7dac757c558bd283dc4577e68cde7",
"lessThan": "f1fbb50b99311b35c2e85cc70341d62082dca4b5",
"versionType": "git"
},
{
"status": "affected",
"version": "8fdff6a319e7dac757c558bd283dc4577e68cde7",
"lessThan": "137bf034740e5a2734794908d0aff1e0bd7cee6e",
"versionType": "git"
},
{
"status": "affected",
"version": "8fdff6a319e7dac757c558bd283dc4577e68cde7",
"lessThan": "6607f85242577f33d4540a0d1f4a6137f5367058",
"versionType": "git"
},
{
"status": "affected",
"version": "8fdff6a319e7dac757c558bd283dc4577e68cde7",
"lessThan": "ca22c94bdfc22c564ca2e11c87ba4d17ebeaaa9a",
"versionType": "git"
},
{
"status": "affected",
"version": "8fdff6a319e7dac757c558bd283dc4577e68cde7",
"lessThan": "0a235379825e1a6194e43861ee6658e5fc35686d",
"versionType": "git"
},
{
"status": "affected",
"version": "8fdff6a319e7dac757c558bd283dc4577e68cde7",
"lessThan": "d3ed4e6321bb453757044cb9e5ecb30a33f04903",
"versionType": "git"
},
{
"status": "affected",
"version": "8fdff6a319e7dac757c558bd283dc4577e68cde7",
"lessThan": "69ee44e1a23be62318189dc4b37fa4ad94053269",
"versionType": "git"
}
],
"programFiles": [
"sound/usb/endpoint.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "3.5"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "3.5",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.10.265",
"versionType": "semver",
"lessThanOrEqual": "5.10.*"
},
{
"status": "unaffected",
"version": "5.15.216",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.183",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.152",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.104",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.45",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.1.9",
"versionType": "semver",
"lessThanOrEqual": "7.1.*"
},
{
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"sound/usb/endpoint.c"
],
"defaultStatus": "affected"
}
]
}
],
"published": "2026-08-22T16:16:42.480",
"references": [
{
"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",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"vulnStatus": "Received",
"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->packets = urb_packs;\n\tu->buffer_size = maxsize * u->packets;\n\n\tif (fmt->fmt_type == UAC_FORMAT_TYPE_II)\n\t\tu->packets++; /* for transfer delimiter */\n\tu->urb = usb_alloc_urb(u->packets, 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 < urb_ctx->packets; i++) {\n\t\turb->iso_frame_desc[i].offset = offs;\n\t\turb->iso_frame_desc[i].length = ep->curpacksize;\n\t\toffs += ep->curpacksize;\n\t}\n\n\turb->transfer_buffer_length = offs;\n\turb->number_of_packets = urb_ctx->packets;\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->buffer_size, so only capture is affected.\n\nfmt_type comes from the device's 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 <baul.lee@xbow.com>"
}
],
"lastModified": "2026-08-22T16:16:42.480",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}