CVE-2026-74639 (GCVE-0-2026-74639)
Vulnerability from cvelistv5
Published
2026-08-22 15:32
Modified
2026-08-22 15:32
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: ALSA: us144mkii: re-anchor capture URBs on resubmission capture_urb_complete() resubmits each capture URB without anchoring it: usb_get_urb(urb); ret = usb_submit_urb(urb, GFP_ATOMIC); Anchoring is a property of a submission, not of the URB. The giveback path calls usb_unanchor_urb() before urb->complete(), so an URB resubmitted from its own completion handler is off the anchor. The capture URBs are anchored once, at stream start, so from the first completion onward tascam->capture_anchor is empty. tascam_free_urbs(), tascam_disconnect(), tascam_suspend() and the stop-work path all call usb_kill_anchored_urbs(&tascam->capture_anchor) to reap the capture URBs before anything is freed. With the anchor empty those calls return immediately and the URBs stay queued on the host controller. tascam_free_urbs() then returns the capture transfer buffers with usb_free_coherent(), and snd_card_free() releases the snd_card allocation that embeds tascam (card->private_data). The controller completes the queued URBs afterwards, writing device-supplied data into the freed transfer buffer, and capture_urb_complete() dereferences the freed driver object. KASAN on 7.2.0-rc5 (arm64): BUG: KASAN: slab-use-after-free in dummy_timer Write of size 512 at addr ffff000015b62000 __asan_memcpy dummy_timer hrtimer_run_softirq Allocated by task 64: usb_alloc_coherent tascam_alloc_urbs tascam_probe Freed by task 170: usb_free_coherent tascam_free_urbs tascam_disconnect usb_unbind_interface BUG: KASAN: slab-use-after-free in capture_urb_complete Read of size 4 at addr ffff0000170ee878 Freed by task 170: release_card_device snd_card_free tascam_disconnect Restore the usb_anchor_urb() between the reference count bump and the resubmission. That also makes the handler's usb_unanchor_urb() failure arm meaningful again and restores usb_kill_anchored_urbs() as a barrier on the disconnect, suspend and stop-work paths. The anchoring was removed on the premise that the URB is already anchored from the initial submission, which does not hold once the first giveback has run. Discovered by XBOW, triaged by Baul Lee <baul.lee@xbow.com>
Impacted products
Vendor Product Version
Linux Linux Version: 16f14f55141d4c55c3f321f93c328fff7cd6860a
Version: ab1db64912428cdf06a4f9542e16e0575e9ad59f
Version: 5cff1529a2f9b3461a7f5a6e36a86682fc290534
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   Linux Linux Version: 6.18.39   
Version: 7.1.4   
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Show details on NVD website


{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "sound/usb/usx2y/us144mkii_capture.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "7779249561d14b8a17c0c83783225794e24a587d",
              "status": "affected",
              "version": "16f14f55141d4c55c3f321f93c328fff7cd6860a",
              "versionType": "git"
            },
            {
              "lessThan": "a5548ce916594c811bd90ce33d67baa3557a6791",
              "status": "affected",
              "version": "ab1db64912428cdf06a4f9542e16e0575e9ad59f",
              "versionType": "git"
            },
            {
              "lessThan": "2615f0fb90df8cf5a96133ca4be74294ed288604",
              "status": "affected",
              "version": "5cff1529a2f9b3461a7f5a6e36a86682fc290534",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "sound/usb/usx2y/us144mkii_capture.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "6.18.45",
              "status": "affected",
              "version": "6.18.39",
              "versionType": "semver"
            },
            {
              "lessThan": "7.1.9",
              "status": "affected",
              "version": "7.1.4",
              "versionType": "semver"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.45",
                  "versionStartIncluding": "6.18.39",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.9",
                  "versionStartIncluding": "7.1.4",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: us144mkii: re-anchor capture URBs on resubmission\n\ncapture_urb_complete() resubmits each capture URB without anchoring it:\n\n\tusb_get_urb(urb);\n\tret = usb_submit_urb(urb, GFP_ATOMIC);\n\nAnchoring is a property of a submission, not of the URB.  The giveback\npath calls usb_unanchor_urb() before urb-\u003ecomplete(), so an URB\nresubmitted from its own completion handler is off the anchor.  The\ncapture URBs are anchored once, at stream start, so from the first\ncompletion onward tascam-\u003ecapture_anchor is empty.\n\ntascam_free_urbs(), tascam_disconnect(), tascam_suspend() and the\nstop-work path all call usb_kill_anchored_urbs(\u0026tascam-\u003ecapture_anchor)\nto reap the capture URBs before anything is freed.  With the anchor empty\nthose calls return immediately and the URBs stay queued on the host\ncontroller.\n\ntascam_free_urbs() then returns the capture transfer buffers with\nusb_free_coherent(), and snd_card_free() releases the snd_card\nallocation that embeds tascam (card-\u003eprivate_data).  The controller\ncompletes the queued URBs afterwards, writing device-supplied data into\nthe freed transfer buffer, and capture_urb_complete() dereferences the\nfreed driver object.\n\nKASAN on 7.2.0-rc5 (arm64):\n\n  BUG: KASAN: slab-use-after-free in dummy_timer\n  Write of size 512 at addr ffff000015b62000\n   __asan_memcpy\n   dummy_timer\n   hrtimer_run_softirq\n  Allocated by task 64:\n   usb_alloc_coherent\n   tascam_alloc_urbs\n   tascam_probe\n  Freed by task 170:\n   usb_free_coherent\n   tascam_free_urbs\n   tascam_disconnect\n   usb_unbind_interface\n\n  BUG: KASAN: slab-use-after-free in capture_urb_complete\n  Read of size 4 at addr ffff0000170ee878\n  Freed by task 170:\n   release_card_device\n   snd_card_free\n   tascam_disconnect\n\nRestore the usb_anchor_urb() between the reference count bump and the\nresubmission.  That also makes the handler\u0027s usb_unanchor_urb() failure\narm meaningful again and restores usb_kill_anchored_urbs() as a barrier\non the disconnect, suspend and stop-work paths.\n\nThe anchoring was removed on the premise that the URB is already anchored\nfrom the initial submission, which does not hold once the first giveback\nhas run.\n\nDiscovered by XBOW, triaged by Baul Lee \u003cbaul.lee@xbow.com\u003e"
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-22T15:32:18.236Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/7779249561d14b8a17c0c83783225794e24a587d"
        },
        {
          "url": "https://git.kernel.org/stable/c/a5548ce916594c811bd90ce33d67baa3557a6791"
        },
        {
          "url": "https://git.kernel.org/stable/c/2615f0fb90df8cf5a96133ca4be74294ed288604"
        }
      ],
      "title": "ALSA: us144mkii: re-anchor capture URBs on resubmission",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74639",
    "datePublished": "2026-08-22T15:32:18.236Z",
    "dateReserved": "2026-08-15T05:44:03.922Z",
    "dateUpdated": "2026-08-22T15:32:18.236Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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