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CVE-2026-74405
OPP: Fix race between OPP addition and lookup
Published 2026-08-15 (2 months ago) by the Linux kernel CNA. Subsystem drivers/opp. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2026-74405 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 | vulnerable | 6.1.190-1 | No fix published anywhere yet, neither in Debian nor upstream for the series bookworm tracks. Watch the Debian tracker page for this CVE. Advisories for bookworm have historically landed a median of 23 days after publication. |
| Debian 13trixie | vulnerable | 6.12.113-1 | No fix published anywhere yet, neither in Debian nor upstream for the series trixie tracks. Watch the Debian tracker page for this CVE. Advisories for trixie have historically landed a median of 11 days after publication. |
| Debian 14forky | fixed | 7.1.5-1 | Update the kernel and reboot. Fixed in 7.1.5-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.1.5-1 | Update the kernel and reboot. Fixed in 7.1.5-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
A race exists between dev_pm_opp_add_dynamic() and dev_pm_opp_find_freq_exact(): CPU0 (add) CPU1 (lookup) ------------------------------- ------------------------------ _opp_add() mutex_lock() list_add(&new_opp->node, head) mutex_unlock() _opp_table_find_key() mutex_lock() dev_pm_opp_get(opp) kref_get() mutex_unlock() kref_init(&new_opp->kref) dev_pm_opp_put() kref_put_mutex() The newly added OPP is inserted into the list before its kref is initialized. A concurrent lookup can find this OPP and increment its reference count while it is still uninitialized, leading to refcount corruption and a potential premature free. Fix this by initializing ->kref and ->opp_table before making the OPP visible via list_add(). This ensures any concurrent lookup observes a fully initialized object. [ Viresh: Updated commit log ]
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/opp/core.c
- What this is
- OPERATING PERFORMANCE POINTS (OPP)MAINTAINERS section matched on drivers/opp/ · linux-pm@vger.kernel.org · Maintained
Check it on the machine
grep -w CONFIG_PM_OPP /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 amd64/cloud-amd64, arm64/cloud-arm64
- trixie, forky, sidYnot built on amd64/cloud-amd64
- Y
- built in where it is built at all; some flavours do not build it
- Build switch
- CONFIG_PM_OPP
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
- 2026-08-15 (2 months ago)source
- CVSS
- 7.8 high
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Hsource recompute it - Attack vector
- local (AV:L)source
- EPSS
- 0.13%, higher than 2.2% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- drivers/opp
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 4.11 | 6.18.40 | 46696b0b2123 |
| 4.11 | 7.1.5 | bb75bd7d9ae7 |
| 4.11 | 7.2 | f5e1cc9a284b |
Why the CNA scored it this way
Quoted from the kernel CNA's own scoring file, word for word. A highlighted metric carries the most severe value CVSS v3.1 defines for it, which is what pushes the score up. source
- AV:LAttack vector, local
- The bug is in the kernel OPP DVFS core reached only from local cpufreq, devfreq, thermal, and GPU power-management paths (e.g. scmi-cpufreq, mtk-mfg, MSM Adreno) that call dev_pm_opp_add_dynamic() and dev_pm_opp_find_freq_exact(); there is no network, adjacent-radio, or physical-device input into _opp_add().
- AC:LAttack complexity, low
- The attacker can drive the lookup side with parallel CPU/GPU load or cpufreq scaling while the kernel concurrently inserts OPPs via _opp_add() during multi-CPU SCMI/GPU power-domain attach and boot cpufreq init; both race participants are attacker-influenceable timing on multi-core ARM/Android/embedded systems.
- PR:LPrivileges required, low
- No init-namespace root is required to hammer dev_pm_opp_find_freq_exact() through normal cpufreq, thermal, or GPU DVFS activity from an unprivileged local process; OPP registration runs automatically in kernel driver attach/probe paths without attacker credentials.
- UI:NUser interaction, none
- Exploitation does not require any victim action beyond the attacker (or kernel) driving DVFS activity; no mount, file open, or other interactive step is needed once the attacker runs concurrent workload or scaling pressure on the target system.
- S:UScope, unchanged
- Refcount corruption causes premature kfree() of a dev_pm_opp slab object still linked in the OPP table, enabling standard kernel memory corruption and privilege escalation within the same OS boundary rather than a VM, IOMMU, or sandbox escape.
- C:HConfidentiality impact, high
- Uninitialized kref_get()/kref_init() races corrupt the OPP refcount and can free the structure while still listed; this use-after-free of kmalloc'd dev_pm_opp memory can expose adjacent heap contents and support arbitrary kernel read primitives.
- I:HIntegrity impact, high
- Premature free of dev_pm_opp while its list node remains reachable allows heap reuse and controlled writes through subsequent allocations, providing a standard path to corrupt kernel objects and achieve arbitrary code execution.
- A:HAvailability impact, high
- Refcount corruption can trigger _opp_kref_release() to kfree() an OPP still referenced by concurrent lookups, causing kernel oops/panic from use-after-free or list corruption during ongoing DVFS operations.