CVE-2026-64373

What the bug is

During system reboot, cpufreq_suspend() is called via the kernel_restart() -> device_shutdown() path. Unlike the normal system suspend path, the reboot path does not call freeze_processes(), so userspace processes and kernel threads remain active. This allows CPU hotplug operations to run concurrently with cpufreq_suspend(). The original code has no synchronization with CPU hotplug, leading to a race condition where governor_data can be freed by the hotplug path while cpufreq_suspend() is still accessing it, resulting in a null pointer dereference: Unable to handle kernel NULL pointer dereference Call Trace: do_kernel_fault+0x28/0x3c cpufreq_suspend+0xdc/0x160 device_shutdown+0x18/0x200 kernel_restart+0x40/0x80 arm64_sys_reboot+0x1b0/0x200 Fix this by adding cpus_read_lock()/cpus_read_unlock() to cpufreq_suspend() to block CPU hotplug operations while suspend is in progress. [ rjw: Changelog edits ]

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/cpufreq/cpufreq.c

What this is

CPU FREQUENCY SCALING FRAMEWORKMAINTAINERS section matched on drivers/cpufreq/ · linux-pm@vger.kernel.org · Maintained

Check it on the machine

grep -w CONFIG_CPU_FREQ /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.

• bookwormYnot built on arm64/cloud-arm64
• trixie, forky, sidYnot built on arm64/cloud-arm64, s390x/s390x
• bookworm · linux-6.12Ynot built on arm64/cloud-arm64

Y

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

Build switch

CONFIG_CPU_FREQ

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

2026-07-25 (3 months ago)source

CVSS

no vector published, unrated

Attack vector

not published

EPSS

0.09%, higher than 0.4% of all CVEssource

CISA KEV

not listedthe KEV catalogue

Debian urgency

not yet assignedsource

Subsystem

drivers/cpufreq

Upstream fixes

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

Introduced	Fixed in	Commit
5.4	5.10.261	6d5dd354c37a
5.4	5.15.212	9103078c7b30
5.4	6.1.178	cd4524ff6567
5.4	6.6.145	73255d702c75
5.4	6.12.96	a0ef2fc89d28
5.4	6.18.39	6e175c00c62d
5.4	7.1.4	a0106b41f9a7
5.4	7.2	a9029dd55696
4.4.198	0	0
4.9.198	0	0
4.14.151	0	0
4.19.81	0	0
5.3.8	0	0

Debian advisories