[CVE-2026-46252][MODERATE REGULAR] regulator: core: fix locking in regulator_resolve_supply() error path [ Upstream

[CVE-2026-46252][MODERATE REGULAR] regulator: core: fix locking in regulator_resolve_supply() error path [ Upstream

[AL-KERNEL]

CVE: CVE-2026-46252
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: regulator: core: fix locking in regulator_resolve_supply() error path [ Upstream
Commit: c66e0db0f37290b53c57994f998bb55590364fd0
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=c66e0db0f37290b53c57994f998bb55590364fd0
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-46252
Analysis date: Wed, 03 Jun 2026 15:34:09 -0400
ActionableScore: 3
ActionableScore lower bound: 1
Actionable bucket: Borderline, manual review recommended
Manual review required: YES

Summary:
The regulator core error path could clear and release a supply regulator with insufficient locking after a failed late enable operation, leading primarily to lockdep warnings or crash risk, with only weak evidence of a broader stale-pointer lifetime issue.

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

The original Linux kernel CVE announcement for CVE-2026-46252 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-46252

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 REGULAR
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-2026-46252	MODERATE	CHECK	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:H/PR:H/UI:N/S:U/C:L/I:L/A:H';CWE-667;CWE-362;*CWE-664;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '5.2';DESCR 'The regulator core error path in regulator_resolve_supply used _regulator_put after a late supply regulator enable failure without holding regulator_list_mutex, which can trigger a lockdep warning. The same path cleared rdev supply without taking the regulator locks, so concurrent regulator core code could observe or use the supply pointer while it is being disconnected and released. For the CVSS the PR:H is used because reliable triggering normally requires administrative control over driver probe, regulator configuration, module load, or device management rather than ordinary local user access. The issue is not network reachable and is tied to local kernel device management paths. Impact is primarily availability through warning or crash on systems with panic_on_warn, with limited worst case concern for stale pointer use due to the locking race.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline, manual review recommended (with actual score 2) 	MAYBE	LOCK WARNONLY LEAK ERRORPATH HARDWARE  INCREASED_FROM_LOW_BASED_ON_REQUIREMANUALCHECK DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN5	-	-	checked

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

ActionableScore=3
ActionableScoreLower=1

## 1. ActionableScore

* Conservative score: 1
* Paranoid score: 3
* Final recommended bucket: **Borderline, manual review recommended**

## 2. Signal breakdown

Conservative signals:

* Availability impact realistic: +1. The visible symptom is a lockdep warning, and it may become a crash only on systems configured with panic_on_warn or similar strict debugging policy.
* Requires admin/root/CAP or equivalent device-management control: -2. Reliable triggering normally requires control over driver probe, regulator topology, device initialization, or failure injection in privileged kernel/device-management paths.
* Broad/default/common subsystem: +1. The regulator core is widely used, especially on embedded and mobile platforms, but the specific error path is not a common userspace-facing interface.
* Conservative total: 1.

Paranoid additional signals:

* Weak/indirect corruption candidate: +1. The patch explicitly says concurrent access to rdev must be prevented while clearing the supply pointer, which suggests a possible stale pointer or inconsistent object state concern.
* Real lifetime corruption concern: +1. The error path releases a regulator reference after a failed enable path, and the previous code used an internal put helper with incorrect locking.
* Privileged kernel/device-management memory corruption path: +1. The affected code runs in a trusted regulator core device-management path, where object lifetime mistakes may affect kernel-owned regulator structures.
* No hard remote or unprivileged trigger is evident. No strong reclaim primitive, controlled overwrite, arbitrary write, or demonstrated LPE path is shown.
* Paranoid total: 3.

## 3. Reachability analysis

The bug is reachable through regulator resolution during driver/device initialization or deferred probe style paths when late enabling of a supply regulator fails. In typical deployments, an attacker would need administrative control over device configuration, module or driver loading, firmware/device behavior, or fault injection to trigger it reliably.

Namespaces and containers do not obviously lower the privilege requirement because regulator core management is not normally delegated to unprivileged containers. The issue is not network reachable. Realistic exploitation conditions are narrow and platform dependent.

## 4. Severity interpretation

This behaves mostly like an ordinary Moderate or Low-like kernel correctness issue in the conservative view. The demonstrated impact is a lockdep warning and possibly availability impact on strict debug or panic_on_warn systems.

The paranoid view treats it as borderline because the patch adds locking around clearing and releasing a shared pointer. That creates a weak lifetime or stale-pointer concern, but there is no evidence of attacker-controlled reclaim, arbitrary write, object confusion, or a practical privilege-escalation path.

## 5. One-sentence report phrase

The regulator core error path could clear and release a supply regulator with insufficient locking after a failed late enable operation, leading primarily to lockdep warnings or crash risk, with only weak evidence of a broader stale-pointer lifetime issue.

## 6. Manual review recommendation

MANUAL CHECK RECOMMENDED.

Manual review is recommended because this is a locking and lifetime fix around a pointer release path in a core kernel subsystem. It does not look like an Important-class issue without additional evidence, but it should not be blindly auto-closed solely as a harmless warning.

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

Patch: regulator: core: fix locking in regulator_resolve_supply() error path [ Upstream
Commit: c66e0db0f37290b53c57994f998bb55590364fd0
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=c66e0db0f37290b53c57994f998bb55590364fd0

Changed files:
  drivers/regulator/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=c66e0db0f37290b53c57994f998bb55590364fd0

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

The original Linux kernel CVE announcement for CVE-2026-46252 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-46252

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:L
  The Best / paranoid CVSS vector: AV:L/AC:H/PR:H/UI:N/S:U/C:L/I:L/A:H
  The Best / paranoid CVSS score: 5.2

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: 1
  Paranoid ActionableScore: 3

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: NO
Published priority for this report (same as in Subject): MODERATE REGULAR

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).