CVE-2026-80861

Status: UPDATED  |  Advisory ID: CVE-2026-80861

Key Details

Affected Products, Subsystems & Sectors

What to Know

In the Linux kernel, the following vulnerability has been resolved:

usb: xhci: bail out of setup if the controller is inaccessible

xhci_gen_setup() locates the operational registers using the capability

length read from the very first register:

xhci->op_regs = hcd->regs +

HC_LENGTH(readl(&xhci->cap_regs->hc_capbase));

If the controller is dead or has dropped off the bus, that read returns

~0, HC_LENGTH() truncates it to 0xff, and op_regs ends up 0xff bytes

past the page-aligned MMIO base, i.e. unaligned. The first access

through it, xhci_halt() -> xhci_handshake() reading op_regs->status, is

then an unaligned readl() on device memory. arm64 faults on unaligned

device accesses, so instead of xhci_handshake() catching the all-ones

value and returning -ENODEV, setup oopses:

xhci-pci-renesas 0005:08:00.0: Unable to change power state from D3cold to D0, device inaccessible

xhci-pci-renesas 0005:08:00.0: xHCI Host Controller

xhci-pci-renesas 0005:08:00.0: new USB bus registered, assigned bus number 1

Unable to handle kernel paging request at virtual address ffff80030a770103

ESR = 0x0000000096000021

FSC = 0x21: alignment fault

Internal error: Oops: 0000000096000021 [#1] SMP

pc : xhci_halt [xhci_hcd]

Call trace:

xhci_halt

xhci_gen_setup

xhci_pci_setup

usb_add_hcd

usb_hcd_pci_probe

xhci_pci_common_probe

xhci_pci_renesas_probe

This was hit with a Renesas uPD720201 that failed to power up ("Unable

to change power state from D3cold to D0, device inaccessible") yet still

reached the HCD probe path.

Read the capability register once, and if it reads back the all-ones

value (as xhci_handshake() and xhci_reset() already test for), abort

setup with -ENODEV before op_regs is derived from it. Reading it once

also avoids re-reading a register that may change under a concurrent

hot-removal. (NVD)

What to Do

Monitor Linux's web page for any future patch releases.

References