CVE-2026-90311

What the bug is

The current code creates one hwmon device per thermal zone type and that device is registered under the first thermal zone of the given type. That turns out to be problematic when the thermal zone holding the hwmon device is removed. For example, say that there are two ACPI thermal zones on a system /sys/devices/virtual/thermal/thermal_zone0/ /sys/devices/virtual/thermal/thermal_zone1/ The current code registers a hwmon class device for thermal_zone0 only: /sys/devices/virtual/thermal/thermal_zone0/hwmon0/ because the type is "acpitz" for both of them, but it adds a sysfs attribute that belongs to thermal_zone1 under it: /sys/devices/virtual/thermal/thermal_zone0/hwmon0/temp2_input There is also /sys/devices/virtual/thermal/thermal_zone0/hwmon0/temp1_input which belongs to thermal_zone0. When thermal_zone0 is removed, say because the ACPI thermal driver is unbound from the underlying platform device, thermal_remove_hwmon_sysfs() skips the removal of hwmon0 because of the temp2_input attribute belonging to thermal_zone1 which effectively prevents thermal_zone0 removal from making progress. Address this by making thermal_remove_hwmon_sysfs() remove the entire hwmon class device interface for the given thermal zone type when the thermal zone device holding it is removed. To prevent races with thermal_add_hwmon_sysfs() that may interfere with this, carry out the entire addition and removal of hwmon sysfs interfaces for thermal zones under thermal_hwmon_list_lock. Also adjust the layout of the labels in thermal_add_hwmon_sysfs() to the current kernel coding style to align with the new "unlock" label.

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/thermal/thermal_hwmon.c

What this is

THERMALMAINTAINERS section matched on drivers/thermal/ · linux-pm@vger.kernel.org · Supported

Check it on the machine

grep -wE 'CONFIG_THERMAL|CONFIG_THERMAL_HWMON' /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 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.

• bookworm, trixie, forky, sidYnot built on amd64/cloud-amd64, arm64/cloud-arm64

Y

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

Build switches

CONFIG_THERMAL, CONFIG_THERMAL_HWMON

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

2026-09-17 (31 days ago)source

CVSS

no vector published, unrated

Attack vector

not published

EPSS

0.21%, higher than 10.0% of all CVEssource

CISA KEV

not listedthe KEV catalogue

Debian urgency

not yet assignedsource

Subsystem

drivers/thermal

Upstream fixes

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

Introduced	Fixed in	Commit
4.19	6.18.57	9b405b3e7e13
4.19	7.2.6	4fa8915f40f7
4.19	7.3	2b57e24d34b2