[CVE-2026-72396][LOW] hwmon: adm1275: Prevent reading uninitialized stack [ Upstream

[CVE-2026-72396][LOW] hwmon: adm1275: Prevent reading uninitialized stack [ Upstream

[AL-KERNEL]

CVE: CVE-2026-72396
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: hwmon: adm1275: Prevent reading uninitialized stack [ Upstream
Commit: 57d583f069fa9d3d0c0831e34b967d1f61edae94
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=57d583f069fa9d3d0c0831e34b967d1f61edae94
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72396
Analysis date: Sat, 15 Aug 2026 23:15:46 -0400
ActionableScore: 1
ActionableScore lower bound: 0
Actionable bucket: Ordinary Moderate / Low-like
Manual review required: NO

Summary:
The adm1275 probe path can consume uninitialized stack bytes during PMBus model string comparison when a device returns a short non NUL terminated response, but exploitation is limited to local hardware or privileged device setup and no direct leak, memory corruption, or privilege escalation primitive is shown.

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

The original Linux kernel CVE announcement for CVE-2026-72396 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72396

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: LOW
Manual review required: NO

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
======================================================================

CVE-2026-72396	LOW	CHECK WITH IMPACT FROM ORIG NN LOW	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L';*CWE-457;CWE-908;CWE-125;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:L/I:N/A:N';BEST CVSS score: '4.5';DESCR 'The adm1275 PMBus probe path can read uninitialized stack bytes during device model comparison because i2c_smbus_read_block_data returns a byte count but does not append a string terminator. If a device returns a short model string, strncasecmp can compare beyond the valid returned bytes and consume stale stack content inside block_buffer. For the CVSS the PR:L is used only for the paranoid case where a local user or service has delegated access to trigger probing or control an emulated I2C/PMBus device. The base case is closer to PR:H because normal device probing and I2C device setup are administrator controlled. The issue is not network reachable. Impact is mainly a low confidentiality or policy risk from uninitialized data use, with no supported evidence of kernel memory corruption or privilege escalation.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 1)	YES	WRITE OOB HARDWARE  DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3	NO	NO	checked

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

ActionableScore=1
ActionableScoreLower=0

## 1. ActionableScore

* Conservative score: 0
* Paranoid score: 1
* Final recommended bucket: **Ordinary Moderate / Low-like**::

## 2. Signal breakdown

Conservative signals:

* Firmware-mediated external influence: +1. A malformed or nonconforming PMBus/I2C device can return a short model string.
* Requires admin/root/CAP_* in typical deployments: -2. Device probing and I2C device setup are normally controlled by root or platform firmware.
* Physical-only or rare hardware-only condition: -2. Triggering depends on a specific local hardware or emulated bus/device condition.
* Limited read-only uninitialized stack consumption: +0. The bug is an uninitialized stack read inside `strncasecmp()`, but the patch does not show user-visible disclosure, write corruption, UAF, object replacement, or privilege escalation.

Paranoid signal:

* Confidentiality impact plausible: +1. The comparison may consume stale stack bytes, but there is no demonstrated path that exposes those bytes to userspace or to an attacker-controlled output channel.

Call-site confidence: high. The relevant probe path and fixed stack buffer initialization are present in the supplied patch.

## 3. Reachability analysis

The bug is reachable during `adm1275_probe()` when the driver reads `PMBUS_MFR_MODEL` via `i2c_smbus_read_block_data()` and then compares the returned bytes as a string. In normal deployments, triggering requires control over the physical PMBus/I2C device, firmware-described device presence, or privileged ability to instantiate/probe an emulated I2C device. This is not network reachable and is not a normal local unprivileged syscall or namespace path. Containers do not meaningfully lower privileges unless the container is explicitly delegated access to the relevant I2C bus or device-management interface.

## 4. Severity interpretation

This behaves like a low-severity uninitialized read / validation bug, not an Important-class kernel vulnerability. The theoretical concern is that stale stack bytes influence device-name comparison, but there is no concrete disclosure primitive, no memory corruption write, no UAF, no refcount/lifetime issue, and no realistic privilege-escalation path supported by the patch. The most realistic impact is incorrect matching behavior or very weak confidentiality concern inside a privileged hardware probe path.

## 5. One-sentence report phrase

The adm1275 probe path can consume uninitialized stack bytes during PMBus model string comparison when a device returns a short non NUL terminated response, but exploitation is limited to local hardware or privileged device setup and no direct leak, memory corruption, or privilege escalation primitive is shown.

## 6. Manual review recommendation

NO MANUAL CHECK NEEDED

This can be auto-closed for practical triage unless the affected product exposes I2C/PMBus device emulation or probing to untrusted users. The patch supports only a constrained uninitialized read in a privileged hardware probe path.

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

Patch: hwmon: adm1275: Prevent reading uninitialized stack [ Upstream
Commit: 57d583f069fa9d3d0c0831e34b967d1f61edae94
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=57d583f069fa9d3d0c0831e34b967d1f61edae94

Changed files:
  drivers/hwmon/pmbus/adm1275.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=57d583f069fa9d3d0c0831e34b967d1f61edae94

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

The original Linux kernel CVE announcement for CVE-2026-72396 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72396

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:N/A:N
  The Best / paranoid CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L
  The Best / paranoid CVSS score: 4.5

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: 0
  Paranoid ActionableScore: 1

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: LOW
KPANIC detected for this report: NO
Published priority for this report (same as in Subject): LOW

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).