CVE-2026-64083

What the bug is

adm1266_gpio_get() and adm1266_gpio_get_multiple() both compose the pin-status word as pins_status = read_buf[0] + (read_buf[1] << 8); right after i2c_smbus_read_block_data(), guarding only against an error return. A well-behaved device returns 2 bytes for GPIO_STATUS/PDIO_STATUS, but the helper happily reports a 0- or 1-byte response too. If the device returns 0 bytes, both read_buf slots are uninitialized stack memory; if it returns 1 byte, read_buf[1] is. The composed value then flows through set_bit() into the caller's *bits in adm1266_gpio_get_multiple(), or into the return value of adm1266_gpio_get(), and ends up in userspace via gpiolib (sysfs and the char-dev ioctls). That leaks a few bits of kernel stack per request on any device whose firmware glitch, bus error, or hostile slave produces a short block-read response. Add the missing length check to both call sites and surface a short response as -EIO.

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/hwmon/pmbus/adm1266.c

What this is

HARDWARE MONITORINGMAINTAINERS section matched on drivers/hwmon/ · linux-hwmon@vger.kernel.org · Maintained

Kernel module

none to look for. The file would have gone into adm1266, and Debian does not compile it into that module, so finding adm1266 in lsmod would say nothing about this CVE.

Check it on the machine

grep -wE 'CONFIG_HWMON|CONFIG_PMBUS|CONFIG_SENSORS_ADM1266' /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 4 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, sidn

n

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

Build switches

CONFIG_HWMON, CONFIG_PMBUS, CONFIG_SENSORS_ADM1266

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 2.2% of all CVEssource

CISA KEV

not listedthe KEV catalogue

Debian urgency

not yet assignedsource

Subsystem

drivers/hwmon

Upstream fixes

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

Introduced	Fixed in	Commit
5.10	5.10.258	fd9196aad9e5
5.10	5.15.209	ee4799becf7d
5.10	6.1.175	c603b6c6840a
5.10	6.6.142	a2d1c819348b
5.10	6.12.92	ae25cf2ea9eb
5.10	6.18.34	eb3cd9bb5904
5.10	7.0.11	64fa9328948d
5.10	7.1	a7232f68c43c