CVE-2026-80861

What the bug is

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.

Where it lives

The fix touches these files. If the subsystem is one you do not use, the practical exposure is lower, though the package is still the vulnerable one.

drivers/usb/host/xhci.c

What this is

USB XHCI DRIVERMAINTAINERS section matched on drivers/usb/host/xhci* · linux-usb@vger.kernel.org · Supported

Check it on the machine

grep -wE 'CONFIG_OF|CONFIG_PCI|CONFIG_USB|CONFIG_USB_EHCI_HCD|CONFIG_USB_FHCI_HCD|CONFIG_USB_FOTG210_HCD|CONFIG_USB_FSL_USB2|CONFIG_USB_GADGET|CONFIG_USB_ISP116X_HCD|CONFIG_USB_ISP1362_HCD|CONFIG_USB_MAX3421_HCD|CONFIG_USB_OHCI_HCD|CONFIG_USB_PCI|CONFIG_USB_PHY|CONFIG_USB_R8A66597_HCD|CONFIG_USB_SL811_HCD|CONFIG_USB_SUPPORT|CONFIG_USB_U132_HCD|CONFIG_USB_UHCI_HCD|CONFIG_USB_XEN_HCD|CONFIG_USB_XHCI_HCD' /boot/config-$(uname -r)

Reads the booted kernel's own configuration, on the machine and nowhere else. =y is built in, =m is a module, and an is not set line means the code is not there.

Show whether Debian builds this, per release

Debian does not build this code. In 5 releases below, every kernel flavour Debian publishes has the switch off, so the vulnerable file is compiled into no kernel binary Debian ships.

• bookworm, trixie, forky, sid, bookworm · linux-6.12n

n

not enabled on any flavour - this release does not build the code

Build switches

CONFIG_OF, CONFIG_PCI, CONFIG_USB, CONFIG_USB_EHCI_HCD, CONFIG_USB_FHCI_HCD, CONFIG_USB_FOTG210_HCD, CONFIG_USB_FSL_USB2, CONFIG_USB_GADGET, CONFIG_USB_ISP116X_HCD, CONFIG_USB_ISP1362_HCD, CONFIG_USB_MAX3421_HCD, CONFIG_USB_OHCI_HCD, CONFIG_USB_PCI, CONFIG_USB_PHY, CONFIG_USB_R8A66597_HCD, CONFIG_USB_SL811_HCD, CONFIG_USB_SUPPORT, CONFIG_USB_U132_HCD, CONFIG_USB_UHCI_HCD, CONFIG_USB_XEN_HCD, CONFIG_USB_XHCI_HCD

Reads as

all on means the file is compiled; any one off means it is not.

From the configuration Debian publishes for every kernel flavour it builds. It covers only the architectures Debian ships a linux-config package for, and nothing about a kernel you built yourself. Debian's own status above stays authoritative about the source package.MAINTAINERS kbuild Makefiles Debian linux-config packages

Signals

Published

2026-09-04 (44 days ago)source

CVSS

no vector published, unrated

Attack vector

not published

EPSS

0.16%, higher than 4.9% of all CVEssource

CISA KEV

not listedthe KEV catalogue

Debian urgency

not yet assignedsource

Subsystem

drivers/usb

Upstream fixes

The versions the CNA records as introducing and fixing this, and the commit for each. source

Introduced	Fixed in	Commit
2.6.31	6.6.158	301f4a3303b2
2.6.31	6.12.111	70706dbcf122
2.6.31	6.18.51	c051f66b6216
2.6.31	7.1.13	bf84c6b02649
2.6.31	7.2.3	0b31744f70c5
2.6.31	7.3	78203d5b54a4

Debian advisories