FKIE_CVE-2026-74682

Vulnerability from fkie_nvd - Published: 2026-08-22 16:16 - Updated: 2026-08-22 16:16
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
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/0a235379825e1a6194e43861ee6658e5fc35686d
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/137bf034740e5a2734794908d0aff1e0bd7cee6e
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6607f85242577f33d4540a0d1f4a6137f5367058
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/69ee44e1a23be62318189dc4b37fa4ad94053269
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6af5f29af7711233ae68d3b25c15d67478468900
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ca22c94bdfc22c564ca2e11c87ba4d17ebeaaa9a
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/d3ed4e6321bb453757044cb9e5ecb30a33f04903
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/f1fbb50b99311b35c2e85cc70341d62082dca4b5
Impacted products
Vendor Product Version
To clipboard 

{
  "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"
    }
  ],
  "id": "CVE-2026-74682",
  "lastModified": "2026-08-22T16:16:42.480",
  "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"
}



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