CVE-2026-64465 usb: xhci: Fix sleep in atomic context in xhci_free_streams()
A local attacker with physical access can cause a kernel crash by disconnecting a USB device with active stream endpoints, leading to denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-64465?
CVE-2026-64465 is a denial of service vulnerability in Linux, published on 25 Jul 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official description
In the Linux kernel, the following vulnerability has been resolved:
usb: xhci: Fix sleep in atomic context in xhci_free_streams()
When a USB device with active stream endpoints is disconnected, xhci_free_streams() is called from the hub_event workqueue to free the stream resources. It calls xhci_free_stream_info() while holding xhci->lock with irqs disabled.
xhci_free_stream_info() invokes xhci_free_stream_ctx(), which calls dma_free_coherent() for large stream context arrays.
dma_free_coherent() can sleep (e.g. via vunmap), triggering a BUG when called from atomic context.
Call trace: dma_free_attrs+0x174/0x220 xhci_free_stream_info+0xd0/0x11c xhci_free_streams+0x278/0x37c usb_free_streams+0x98/0xc0 usb_unbind_interface+0x1b8/0x2f8 device_release_driver_internal+0x1d4/0x2cc device_release_driver+0x18/0x28 bus_remove_device+0x160/0x1a4 device_del+0x1ec/0x350 usb_disable_device+0x98/0x214 usb_disconnect+0xf0/0x35c hub_event+0xab4/0x19ec process_one_work+0x278/0x63c
Fix this by saving the stream_info pointers and clearing the ep references under the lock, then calling xhci_free_stream_info() outside the lock where sleeping is allowed.
Which versions are affected by CVE-2026-64465?
How do I fix CVE-2026-64465?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-64465 being exploited?
There is no known exploitation of CVE-2026-64465 in the wild and no public exploit code.
Sources
Also known as AZL-93912, BELL-CVE-2026-64465, DEBIAN-CVE-2026-64465, GHSA-5wmv-5wg4-7mv5, ROOT-OS-UBUNTU-2204-CVE-2026-64465, UBUNTU-CVE-2026-64465.