CVE-2026-74639 (GCVE-0-2026-74639)
Vulnerability from cvelistv5
Published
2026-08-22 15:32
Modified
2026-08-22 15:32
Severity ?
VLAI Severity ?
EPSS score ?
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>
References
Impacted products
{
"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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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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