CVE-2026-64014

What the bug is

nexio_read_data() pulls data_len and x_len from a packed __be16 header in the device's interrupt packet and then walks packet->data[0..x_len) and packet->data[x_len..data_len) comparing each byte against a threshold. Both fields are 16-bit on the wire (max 65535). The existing adjustments shave at most 0x100 / 0x80 off, so the loop bound can still reach roughly 0xfeff. The URB transfer buffer for NEXIO is rept_size (1024) bytes from usb_alloc_coherent(), with the first 7 occupied by the packed header — so packet->data[] has 1017 valid bytes. read_data() callbacks are not given urb->actual_length, and nothing else bounds the walk. A device that lies about its length can get a ~64 KiB out-of-bounds read past the coherent DMA allocation. The first index whose byte exceeds NEXIO_THRESHOLD lands in begin_x / begin_y and from there into the reported touch coordinates, so adjacent kernel memory contents leak to userspace as ABS_X / ABS_Y events. Far enough out, the read can also hit an unmapped page and fault. Fix this all by clamping data_len to the buffer's data[] capacity and x_len to data_len.

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/input/touchscreen/usbtouchscreen.c

What this is

INPUT (KEYBOARD, MOUSE, JOYSTICK, TOUCHSCREEN) DRIVERSMAINTAINERS section matched on drivers/input/ · linux-input@vger.kernel.org · Maintained

Kernel module

usbtouchscreen

Check it on the machine

grep -wE 'CONFIG_INPUT|CONFIG_INPUT_TOUCHSCREEN|CONFIG_TOUCHSCREEN_USB_COMPOSITE' /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.

lsmod | grep -w usbtouchscreen

Prints a line if that module is loaded right now, and nothing if it is not. One that is not loaded can still be loaded later by anything that needs it.

Show whether Debian builds this, per release

Debian builds this, but not on every flavour. At least one release below builds the code on some of its kernel flavours and not on others, so the answer depends on the architecture and flavour installed.

• bookwormMnot built on amd64/cloud-amd64, arm64/cloud-arm64
• trixieMnot built on amd64/cloud-amd64, arm64/cloud-arm64, armel/rpi, riscv64/riscv64, s390x/s390x
• forky, sidMnot built on amd64/cloud-amd64, arm64/cloud-arm64, loong64/loong64, riscv64/riscv64, s390x/s390x

M

a module where it is built at all; some flavours do not build it

Build switches

CONFIG_INPUT, CONFIG_INPUT_TOUCHSCREEN, CONFIG_TOUCHSCREEN_USB_COMPOSITE

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

2026-07-19 (3 months ago)source

CVSS

no vector published, unrated

Attack vector

not published

EPSS

0.13%, higher than 2.0% of all CVEssource

CISA KEV

not listedthe KEV catalogue

Debian urgency

not yet assignedsource

Subsystem

drivers/input

Upstream fixes

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

Introduced	Fixed in	Commit
2.6.34	5.10.259	45c829e5eb3b
2.6.34	5.15.210	e7cdcb266ba0
2.6.34	6.1.176	95f47331dfde
2.6.34	6.6.143	d883312061cc
2.6.34	6.12.93	103d2de9f505
2.6.34	6.18.35	0ca809ea8e03
2.6.34	7.0.12	7585b6aa55d8
2.6.34	7.1	2905281cbda5