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CVE-2026-97904
cpufreq: initialize policy rwsem before sysfs publication
Published 2026-09-25 (24 days ago) by the Linux kernel CNA. Subsystem drivers/cpufreq. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2026-97904 in every release this site tracks, and what each one means in practice. Every status below is the one the Debian Security Team publishes for this CVE. source
| Release | Status | Version | What this means |
|---|---|---|---|
| Debian 12bookworm | fixedDLA-4841-1 · 2026-10-17 · text | 6.1.190-1 | Update the kernel and reboot. DLA-4841-1 shipped the fix on 2026-10-17, in 6.1.190-1. A running kernel keeps the old code until the machine restarts. |
| Debian 13trixie | fixedDSA-6528-1 · 2026-09-29 · text | 6.12.111-1 | Update the kernel and reboot. DSA-6528-1 shipped the fix on 2026-09-29, in 6.12.111-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.2.7-1 | Update the kernel and reboot. Fixed in 7.2.7-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.2.7-1 | Update the kernel and reboot. Fixed in 7.2.7-1. A running kernel keeps the old code until the machine restarts. |
| Debian 12bookworm · linux-6.12 | fixedDLA-4817-1 · 2026-10-04 · text | 6.12.111-1~deb12u1 | Update the kernel and reboot. DLA-4817-1 shipped the fix on 2026-10-04, in 6.12.111-1~deb12u1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
cpufreq_policy_alloc() initializes policy->rwsem after kobject_init_and_add() has created the policy sysfs directory and its default attributes. A sysfs access can therefore reach a policy callback before the semaphore has been initialized. Initialize policy->rwsem before publishing the policy kobject so sysfs callbacks always see an initialized semaphore.
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 | c9d8435814f2 |
| 4.2 | 5.15.222 | 82a54923700d |
| 4.2 | 6.1.189 | b14987a0f737 |
| 4.2 | 6.6.158 | b22193eea2ce |
| 4.2 | 6.12.111 | dc11263cb05e |
| 4.2 | 6.18.53 | 27c9b491bf76 |
| 4.2 | 7.2.7 | 2cee937f779f |
| 4.2 | 7.3 | 3e5d1bf4bd68 |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DLA-4841-1 | 2026-10-17 | bookworm 6.1.190-1 | tracker |
| DLA-4817-1 | 2026-10-04 | bookworm 6.12.111-1~deb12u1 | tracker |
| DSA-6528-1 | 2026-09-29 | trixie 6.12.111-1 | tracker |
Why the CNA scored it this way
The kernel CNA published no CVSS vector and no reasoning for CVE-2026-97904, which is why it is shown as unrated rather than given an invented score. 6,405 of the 20,413 CVEs here carry reasoning; this is not one of them.