CVE-2026-64331

Medium

Description

In the Linux kernel, the following vulnerability has been resolved: usbip: vudc: fix NULL deref in vep_dequeue() vep_alloc_request() wasn't initializing vrequest->udc, so cancellations on the FunctionFS AIO path were arriving in vep_dequeue without a valid UDC reference. Since vrequest->udc is never actually properly used anywhere, we opt to remove it, and update vep_dequeue to obtain a reference to the udc with ep_to_vudc(), consistent with the other vep_ ops. AFAICT this bug has existed for ~10 years. Seems that nobody has really stressed the FunctionFS AIO path on usbip's vudc. I tested this fix in a QEMU aarch64 guest driving FunctionFS endpoints via AIO. Before the fix, running `usbip attach` from the host would cause the guest to oops with the following backtrace: Call trace: vep_dequeue+0x1c/0xe4 (P) usb_ep_dequeue+0x14/0x20 ffs_aio_cancel+0x24/0x34 __arm64_sys_io_cancel+0xb0/0x124 do_el0_svc+0x68/0x100 el0_svc+0x18/0x5c el0t_64_sync_handler+0x98/0xdc el0t_64_sync+0x154/0x158

SeverityMedium
CVSS5.5
Exploit probability—
ProductLinux Kernel
PublishedJul 25, 2026
First seenJul 25, 2026

How to fix

Affected products

ProductAffected versionsFixed in
linux linux_kernel4.7 ≤ v < 5.10.261, 5.11 ≤ v < 5.15.212, 5.16 ≤ v < 6.1.178, 6.2 ≤ v < 6.6.145, 6.7 ≤ v < 6.12.96, 6.13 ≤ v < 6.18.39, 6.19 ≤ v < 7.1.4, 7.25.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.96, 6.18.39, 7.1.4

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