VulnerabilityPublished 22 Aug 2026Updated 30 Sep 2026

CVE-2026-74639: Linux kernel · ALSA: us144mkii: re-anchor capture URBs on resubmission

Affects Linux kernelSource GCVE Database

Not known to be exploited.

Data as of 26 Oct 2026, 15:59 UTC

Severity

Medium

Rated by Threat Radar · CVSS not yet scored by NVD

EPSS: 0.2% chance of exploitation in 30 days – higher than 10% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

Exploitation evidence

Disclosed: evidence found.
CVE published 22 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

ghsa-hx28-f548-xhmf

What to do

Affected software

Product	Affected	Fixed in
Ubuntu 26.04 LTSlinux`pkg:deb/ubuntu/linux?arch=source&distro=resolute`Other threats	Affected 6.17.0-5.5 – 7.0.0-34.34 22 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-aws`pkg:deb/ubuntu/linux-aws?arch=source&distro=resolute`Other threats	Affected 6.17.0-1002.2 – 7.0.0-1013.13 14 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-azure`pkg:deb/ubuntu/linux-azure?arch=source&distro=resolute`Other threats	Affected 6.17.0-1003.3 – 7.0.0-1014.14 14 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-azure-fde`pkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resolute`Other threats	Affected 7.0.0-1003.3 – 7.0.0-1013.13 8 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-gcp`pkg:deb/ubuntu/linux-gcp?arch=source&distro=resolute`Other threats	Affected 6.17.0-1002.2 – 7.0.0-1013.13 12 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-gke`pkg:deb/ubuntu/linux-gke?arch=source&distro=resolute`Other threats	Affected 7.0.0-1002.3 – 7.0.0-1007.8 5 affected builds	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A fix is available and has been applied to the Linux kernel to restore proper anchoring of URBs on resubmission in the ALSA us144mkii driver. Users should update to a kernel version that includes this patch. Since this is a kernel-level issue, applying the official kernel update is the recommended remediation.

Description

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>

Impact

This vulnerability can lead to use-after-free conditions in kernel memory, potentially causing kernel crashes or memory corruption. The device can write data into freed memory buffers, which may destabilize the kernel or lead to undefined behavior. No known exploits in the wild have been reported.

Summary

The vulnerability in the Linux kernel ALSA us144mkii driver arises because capture URBs are resubmitted in the capture_urb_complete() function without re-anchoring them. Anchoring is a submission property that ensures URBs can be properly tracked and killed on disconnect or suspend. Since the URBs are only anchored once at stream start, subsequent resubmissions are off-anchor, causing calls to usb_kill_anchored_urbs() to return immediately without reaping the URBs. When the driver frees the transfer buffers and associated structures, the USB host controller may still complete queued URBs, writing data into freed memory and causing use-after-free conditions. The fix restores usb_anchor_urb() calls between reference count increment and resubmission, ensuring proper anchoring and safe cleanup. This vulnerability was discovered by XBOW and triaged by Baul Lee.

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 22 Aug 2026, 23:40 UTC

Technical details

References

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