CVE-2026-97905

What the bug is

cpufreq_policy_alloc() allocates policy->cpus with alloc_cpumask_var(), i.e. without __GFP_ZERO, unlike the sibling related_cpus and real_cpus masks. With CONFIG_CPUMASK_OFFSTACK=y the mask is a separate kmalloc_node() allocation, so its bitmap holds whatever the slab allocator left behind: cpufreq_online() cpufreq_policy_alloc() alloc_cpumask_var(&policy->cpus) /* bitmap is uninitialized */ kobject_init_and_add() /* policy%u/ appears in sysfs */ cpufreq_policy_online() cpumask_copy(policy->cpus, cpumask_of(cpu)) /* first valid value */ This leaves a window in which the sysfs attributes are already reachable while policy->cpus is still garbage. show()/store() gate on policy_is_inactive(), i.e. cpumask_empty(policy->cpus), so a non-zero bitmap makes them run the attribute callbacks on a policy that is not initialized yet. Fix this by using zalloc_cpumask_var() for policy->cpus.

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

2026-09-25 (24 days ago)source

CVSS

no vector published, unrated

Attack vector

not published

EPSS

0.21%, higher than 10.5% 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
4.2	5.10.271	e13370c5b549
4.2	5.15.222	e807920031ca
4.2	6.1.189	ca52482508b3
4.2	6.6.158	06f273d29e5e
4.2	6.12.111	0de2f3918fbb
4.2	6.18.53	6e166b9281de
4.2	7.2.7	bbc0472d2270
4.2	7.3	54d37bcf2f49

Debian advisories