[CVE-2026-74271][MODERATE 7.0] power: supply: core: fix supplied_from allocations [ Upstream

[CVE-2026-74271][MODERATE 7.0] power: supply: core: fix supplied_from allocations [ Upstream

[AL-KERNEL]

CVE: CVE-2026-74271
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: YES
Patch: power: supply: core: fix supplied_from allocations [ Upstream
Commit: ae55e4bf18ee0c4c170797dd65e17dbdf644fcf2
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=ae55e4bf18ee0c4c170797dd65e17dbdf644fcf2
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74271
Analysis date: Sat, 15 Aug 2026 11:30:28 -0400
ActionableScore: 7
ActionableScore lower bound: 5
Actionable bucket: Strong Important candidate / Actionable Moderate at minimum
Manual review required: YES

Summary:
An incorrect allocation in the power_supply core can overrun the `supplied_from` pointer array when a device tree `power-supplies` property contains multiple entries, causing kernel memory corruption during device registration with realistic DoS impact and possible integrity impact.

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

The original Linux kernel CVE announcement for CVE-2026-74271 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74271

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.

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AL-KERNEL CLASSIFICATION RESULT
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CVE-2026-74271	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-787;CWE-131;CWE-122;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:L/I:L/A:H';BEST CVSS score: '7';DESCR 'The power_supply core can write past the allocated supplied_from pointer array when a device tree power-supplies property contains multiple entries. The vulnerable path allocates space for only one pointer but later indexes psy supplied_from by supply number, which creates an out-of-bounds kernel write during device registration or probing. For the CVSS the PR:L is used for the paranoid score because reliable triggering generally requires local control over device tree data or overlays, and some systems may delegate this control to a reduced capability administrator or service account rather than full host root. The issue is not network reachable and is tied to local platform configuration. Impact is at least local denial of service via kernel memory corruption, and in the worst case may allow confidentiality or integrity impact due to an out-of-bounds write primitive.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Strong Important candidate / Actionable Moderate at minimum (with actual score 7)	YES	NOMEMCHK SIMPLEFIX HARDWARE LINUS  KPANIC INCREASED_TO_MODERATE7_BASED_ON_GUESSCVSS 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=5

## 1. ActionableScore

* Conservative score: 5
* Paranoid score: 7
* Final recommended bucket: **Strong Important candidate / Actionable Moderate at minimum**::

## 2. Signal breakdown

Conservative scoring:

* +2 Memory corruption, strong corruption primitive: the patch fixes an under-allocation where `psy->supplied_from` had space for one pointer but later code indexes `psy->supplied_from[i-1]` for multiple `power-supplies` entries.
* +1 Firmware-mediated external influence: the trigger depends on DTS / device tree supplied configuration rather than a normal remote interface.
* +1 Privileged kernel/device-management memory corruption path: corruption occurs during power_supply device registration / probing in trusted kernel device-management code.
* +1 Reliable kernel crash / strong DoS: an OOB kernel pointer write during probe can plausibly crash the kernel or break device initialization.
* +1 Confidentiality impact plausible: limited, because kernel memory corruption may expose adjacent object state in worst realistic cases, but no direct info leak is shown.
* +1 Integrity impact plausible: OOB pointer writes can corrupt adjacent kernel metadata.
* +1 Availability impact realistic: crash or boot/device initialization failure is realistic.
* -2 Requires admin/root or equivalent in typical deployments: reliable triggering usually requires modifying DTS, firmware data, or privileged DT overlay configuration.
* -1 Corruption primitive constrained: written values are likely kernel-derived pointers and the overwrite target is adjacent allocation state, not an attacker-chosen arbitrary address.

Paranoid additions / changes:

* Weak LPE concern is considered because this is a real OOB write primitive in kernel memory, but not a strong LPE primitive because there is no demonstrated reclaim, arbitrary write, callback overwrite, or type confusion.
* The full privilege penalty is softened in the paranoid interpretation because some systems may delegate DT overlay or platform configuration control to a reduced-capability administrator, service account, test framework, or containerized management component rather than full host root.

## 3. Reachability analysis

The bug is triggered when a power_supply device is registered with a device tree `power-supplies` property containing multiple values. In normal production systems, DTS and firmware-provided hardware description are controlled by the platform vendor or administrator, so a typical attacker needs privileged local or firmware/configuration control. It is not network reachable.

Namespaces usually do not make this directly reachable. However, systems that allow runtime device tree overlays or delegated hardware-management services may reduce the practical privilege requirement from full host root to a less privileged local management context. The affected subsystem is common on embedded, mobile, laptop, and board-style systems, but the vulnerable condition depends on a specific multi-supply DT configuration.

Call-site confidence: high for the allocation and OOB write condition because the patch directly fixes the allocation size used by the later indexed array access. Exploitability confidence: medium-low because attacker control over target and payload is constrained.

## 4. Severity interpretation

This is not an ordinary resource leak or validation-only cleanup. It is a concrete kernel out-of-bounds write caused by allocating the wrong object shape for an array later indexed by supply number.

Realistic impact is most likely local/firmware-mediated DoS or kernel memory corruption during device probing. Practical LPE is not demonstrated, but the bug class and kernel write primitive justify manual review and an actionable score above ordinary Moderate. The paranoid score treats it as an Important candidate because early triage should not auto-close a kernel OOB write in a device-management path.

## 5. One-sentence report phrase

An incorrect allocation in the power_supply core can overrun the `supplied_from` pointer array when a device tree `power-supplies` property contains multiple entries, causing kernel memory corruption during device registration with realistic DoS impact and possible integrity impact.

## 6. Manual review recommendation

MANUAL CHECK REQUIRED

Reason: the patch fixes a concrete OOB write in kernel memory, and although triggering is usually privileged or firmware-mediated, the primitive is strong enough to require human review rather than auto-closure.

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

Patch: power: supply: core: fix supplied_from allocations [ Upstream
Commit: ae55e4bf18ee0c4c170797dd65e17dbdf644fcf2
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=ae55e4bf18ee0c4c170797dd65e17dbdf644fcf2

Changed files:
  drivers/power/supply/power_supply_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=ae55e4bf18ee0c4c170797dd65e17dbdf644fcf2

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

The original Linux kernel CVE announcement for CVE-2026-74271 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74271

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:L/I:L/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: 5
  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).