PT-2026-64552 · Linux · Linux

CVE-2026-64331 · Published 2026-07-25 · Updated 2026-07-25

NVD

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

Related Identifiers

CVE-2026-64331

Affected Products

Linux

References · 9

• https://nvd.nist.gov/vuln/detail/CVE-2026-64331 · Security Note
• https://git.kernel.org/stable/c/0025276175fbbe0dcbf3f84d090b0adee769e9d9 · Note
• https://git.kernel.org/stable/c/347b59e9f96719d89b6ef555d02a18ada1a5846f · Note
• https://git.kernel.org/stable/c/9858c91d9ee6a13c45311569039413729fc9b757 · Note
• https://git.kernel.org/stable/c/c5371e0b91b24159a3ebaa61e70b0980bcf03c0a · Note
• https://git.kernel.org/stable/c/1226293ec9bed3d4cc5b05eeeb811d315ca51652 · Note
• https://git.kernel.org/stable/c/3750f75f29f99c0223601e2ee73ad084adec47bd · Note
• https://git.kernel.org/stable/c/d0ebf9cc7c2ddf95a7cfc654b940bdacb7edde97 · Note
• https://git.kernel.org/stable/c/0443e4416aa1ee97748d1ed904eaf3352c60045e · Note