[CVE-2026-74405][MODERATE 7.0] OPP: Fix race between OPP addition and lookup [ Upstream

[CVE-2026-74405][MODERATE 7.0] OPP: Fix race between OPP addition and lookup [ Upstream

[AL-KERNEL]

CVE: CVE-2026-74405
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: YES
Patch: OPP: Fix race between OPP addition and lookup [ Upstream
Commit: 46696b0b2123475d7f95909435c09808fc5ffd23
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=46696b0b2123475d7f95909435c09808fc5ffd23
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74405
Analysis date: Sat, 15 Aug 2026 05:57:12 -0400
ActionableScore: 7
ActionableScore lower bound: 4
Actionable bucket: Strong Important candidate / Actionable Moderate at minimum
Manual review required: YES

Summary:
A race in the OPP core can expose a newly added dev_pm_opp object before its kref and table pointer are initialized, allowing concurrent lookup to corrupt the reference count and potentially cause premature free, kernel crash, or a UAF candidate requiring manual review.

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ABOUT THIS REPORT
======================================================================

The original Linux kernel CVE announcement for CVE-2026-74405 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74405

The original announcement does not normally provide a security severity
estimate, CVSS assessment, or enough information to determine whether the
reported kernel bug represents a practically relevant security issue.

This report was generated by AL-KERNEL, an AI-assisted Linux kernel
vulnerability analysis system developed by Alexander Larkin. It combines
an autonomous classifier with LLM-assisted technical analysis and a
separate ActionableScore mechanism.

The purpose of this report is to prioritize Linux kernel CVEs before
manual review, identify cases that require prompt investigation, and
support automatic closure of issues that are unlikely to have meaningful
security impact.

Published priority for this report: MODERATE 7.0
Manual review required: YES

A detailed explanation of the methodology and priority rules is included
at the end of this message.

======================================================================
AL-KERNEL CLASSIFICATION RESULT
======================================================================

CVE-2026-74405	MODERATE	CHECK WITH IMPACT FROM ORIG NN MODERATE	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H';CWE-362;*CWE-416;CWE-665;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '7';DESCR 'A race in the OPP core can expose a newly added dev_pm_opp object to lookup before its kref and table pointer are fully initialized. A concurrent dev_pm_opp_find_freq_exact() path can take a reference on this partially initialized object, which can corrupt the reference count and may lead to premature free or use-after-free. For the CVSS the PR:L is used for the paranoid score because reduced capability root, container root, or a delegated power management service that can trigger OPP updates should not be treated as full administrative control in practical risk analysis. The issue is not network reachable and requires local interaction with a platform path that can add and look up dynamic OPP entries. Impact is at least local denial of service via kernel crash and in worst case may allow confidentiality and integrity impact due to memory corruption and should be reviewed manually.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Strong Important candidate / Actionable Moderate at minimum (with actual score 6)	YES	DANGER INIT RACE HARDWARE LINUS KPANIC  KPANIC INCREASED_TO_HIGH_BASED_ON_ACTIONABLESCOREHIGHEREQTHAN6 DECREASED_TO_MODERATE7_BASED_ON_FALSEPOSCHECKOFKP	NO	NO	checked

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ACTIONABLESCORE ANALYSIS
======================================================================

ActionableScore=7
ActionableScoreLower=4

## 1. ActionableScore

* Conservative score: 4
* Paranoid score: 7
* Final recommended bucket: **Strong Important candidate / Actionable Moderate at minimum**::

## 2. Signal breakdown

Conservative signals:

* Memory corruption, strong corruption primitive: +2. The race can corrupt an uninitialized kref and the commit explicitly mentions potential premature free.
* Real lifetime corruption: +1. Refcount corruption can break object lifetime and create a UAF style condition.
* Reliable kernel crash / strong DoS: +1. Premature free or corrupted kref in core kernel PM data structures can realistically crash the kernel.
* Privileged kernel/device-management memory corruption path: +1. OPP is a trusted power-management/device framework path.
* Hard or unreliable race / special timing required: -1. The bug requires a concurrent add and lookup window.

Paranoid additional signals:

* Weak to moderate LPE concern: +1. Refcount corruption and premature free create a plausible UAF review target, although no reclaim or overwrite primitive is demonstrated.
* Confidentiality impact plausible: +1. Only for the paranoid score, because UAF style lifetime corruption can sometimes become a read or object reuse primitive.
* Integrity impact plausible: +1. Only for the paranoid score, because refcount lifetime corruption can sometimes become object corruption if reuse is controllable.

No remote/network signal is applied. No Dirty-Pipe-like or filesystem/page-cache signal is applied.

## 3. Reachability analysis

The affected path is local and kernel-internal through dynamic OPP addition and OPP lookup. A direct unprivileged userspace trigger is not shown by the patch. Practical reachability depends on platform drivers, power-management services, devfreq/cpufreq style control paths, firmware interaction, or vendor-specific interfaces that can add dynamic OPP entries while another path performs lookup.

Namespaces and containers do not automatically make this reachable. However, reduced-capability root, container root, or delegated power-management service accounts should not always be treated as full host root if they can influence the relevant device-management path.

The race is timing-sensitive, but the vulnerable window is real: the object is made visible by list_add() before kref_init() and opp_table initialization.

Call-site confidence: medium. The commit gives the relevant add and lookup interleaving, but not all external driver/user entry points.

## 4. Severity interpretation

Conservatively this is a borderline/manual-review kernel memory lifetime issue rather than an ordinary low-risk DoS. The patch supports refcount corruption and potential premature free, which is stronger than a pure NULL dereference or validation-only fix.

Realistic exploitation evidence is limited because no attacker-controlled reclaim, object replacement, callback control, or arbitrary write primitive is shown. Paranoid scoring is higher because refcount lifetime bugs in core kernel objects can sometimes become UAF-based privilege escalation candidates, especially when a local actor can repeatedly exercise the add/lookup paths.

## 5. One-sentence report phrase

A race in the OPP core can expose a newly added dev_pm_opp object before its kref and table pointer are initialized, allowing concurrent lookup to corrupt the reference count and potentially cause premature free, kernel crash, or a UAF candidate requiring manual review.

## 6. Manual review recommendation

MANUAL CHECK REQUIRED. YES REQUIRES MANUAL CHECK.

Reason: this is a race with refcount corruption and a potential premature-free/UAF condition, so it should not be auto-closed even though practical triggering is platform-dependent and no concrete LPE primitive is demonstrated.

======================================================================
UPSTREAM PATCH SUMMARY
======================================================================

Patch: OPP: Fix race between OPP addition and lookup [ Upstream
Commit: 46696b0b2123475d7f95909435c09808fc5ffd23
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=46696b0b2123475d7f95909435c09808fc5ffd23

Changed files:
  drivers/opp/core.c

Diff excerpt:

Not included in this email. See the upstream URL for the full patch.

Full patch:
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=46696b0b2123475d7f95909435c09808fc5ffd23

======================================================================
DETAILED REPORT METHODOLOGY
======================================================================

The original Linux kernel CVE announcement for CVE-2026-74405 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74405

The original CVE announcement normally does not include a security-level
estimate. In particular, it may not contain a CVSS assessment, an impact
level, or enough information to determine whether the reported bug is a
practically relevant security issue. One purpose of this parallel CVE list
is to provide that missing technical and prioritization information.

The original goal of the AL-KERNEL project was to prioritize Linux kernel
CVE analysis automatically before manual review. The system can also help
identify non-security issues that may be suitable for automatic closure.

This report was generated by AL-KERNEL, an AI-assisted Linux kernel
vulnerability analysis system developed by Alexander Larkin.

The first analysis stage combines an autonomous classifier with additional
LLM-based analysis. The autonomous classifier runs locally on a CPU and is
based on a backpropagation neural network. Together, these mechanisms
produce a technical vulnerability description, identify likely weakness
types, estimate CVSS severity, and provide input for ActionableScore.

Two CVSS estimates are retained because incomplete kernel vulnerability
information often permits more than one defensible interpretation:

  Conservative CVSS vector: AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
  The Best / paranoid CVSS score: 7

The conservative vector represents a lower-impact interpretation.
The Best/paranoid vector intentionally represents a plausible upper-bound
interpretation and should not automatically be treated as demonstrated
real-world impact.

CVSS may also need to be adjusted for a particular Linux deployment,
because actual reachability, privileges, enabled kernel configuration,
hardware, namespaces, exposed device nodes, and other environmental
conditions can differ significantly between systems.

A separate ActionableScore mechanism evaluates practical remediation
urgency. Its analysis may include reachability, attack prerequisites,
subsystem exposure, memory-corruption characteristics, denial-of-service
reliability, and possible confidentiality, integrity, or
privilege-escalation impact.

  Conservative ActionableScore: 4
  Paranoid ActionableScore: 7

The final base severity is taken directly from the second tab-separated
field of the AL-KERNEL classification result. ActionableScore does not
replace or independently override that final AL-KERNEL decision, and
if ActionableScore adjusted impact level of ALKERNEL, then you would see
self-readable flags above like INCREASED_TO_HIGH_BASED_ON_ACTIONABLESCOREHIGHEREQTHAN7.

For an AL-KERNEL result of MODERATE, this report uses the following
additional presentation split:

  ActionableScore below 5   -> MODERATE REGULAR
  ActionableScore 5 or more -> MODERATE 7.0

The distinction between MODERATE REGULAR and MODERATE 7.0 makes it
possible to identify Moderate issues that should receive manual analysis
and fixes before lower-priority MODERATE REGULAR issues. In many cases,
MODERATE REGULAR fixes may wait for a later rebase or routine update.

There is one override in which MODERATE REGULAR becomes MODERATE 7.0
even when the ActionableScore is below 5. When the AL-KERNEL result
contains the KPANIC flag, a MODERATE result is always presented as
MODERATE 7.0. The KPANIC flag selected with few regexps without
usage of AI at all, so it helps to detect cases when Kernel Crash happens
and similar (to filter False-Negative results from the LLM usage).

KPANIC indicates that a reliable kernel crash, kernel panic, or similarly
serious kernel availability impact was identified by the classification
workflow.

AL-KERNEL base severity for this report: MODERATE
KPANIC detected for this report: YES
Published priority for this report (same as in Subject): MODERATE 7.0

These results are intended to support engineering triage. They are
machine-generated estimates, and cases marked for manual review should
be validated by a human security engineer before final disposition.
For more info read docs linked from here: https://kernelcve.org/
(and you can submit you own patch there to generate such a report
for non-existant CVE-id yet).

Note that in many cases this AI tool selects higher severity, than
real is (means you can expect Importants instead of Moderate 7.0 or
Moderates 7.0 instead of regular Moderates). If you see such cases,
please use reply email interface to add additional manual analyses
info to this particular CVE.
And please, please, let me know when you see Lows instead of Importants
or Important instead of Low (because particular for such cases I
need to tune this AI tool to make it better for this one and next similar).
My contact email for such notifications is alexanjelausa@gmail.com (and both
send reply to CVE record itself too and see "reply" button below for howto reply).