[CVE-2026-98673][LOW] iio: adc: pac1934: check ACPI label duplication

[AL-KERNEL <alkernel@kernelcve.org>]

CVE: CVE-2026-98673
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: iio: adc: pac1934: check ACPI label duplication
Commit: b7ac07d0b1a44bf644733298e80fd1f22e2f0cc1
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=b7ac07d0b1a44bf644733298e80fd1f22e2f0cc1
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98673
Analysis date: Sat, 24 Oct 2026 06:27:07 -0400
ActionableScore: 1
ActionableScore lower bound: unknown
Actionable bucket: Ordinary Moderate
Manual review required: NO

Summary:
Unchecked `devm_kmemdup()` failure during PAC1934 ACPI probing can cause a NULL-derived terminating-byte write and kernel Oops.

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

The original Linux kernel CVE announcement for CVE-2026-98673 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98673

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
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CVE-2026-98673	LOW	https://www.kernelcve.org/list/?q=CVE-2026-98673 CHECK WITH IMPACT FROM ORIG NN MODERATE | AEGIS IMPACT LOW AEGIS_AS=1 LEGACY=LOW RESULT=SAME (final reconciliation agrees; DECISION: both 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:N/I:N/A:H';CWE-690;**CWE-476;CWE-252;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '4.7';DESCR 'An unchecked devm_kmemdup failure leaves info labels idx as NULL and the following terminating byte write uses that missing allocation. The most credible result is a kernel oops during PAC1934 ACPI device probing, with possible system panic when panic on oops policy is enabled. For the CVSS the PR:H base value reflects that reliable triggering normally requires control over ACPI configuration or privileged device reprobe operations. For the CVSS the PR:L paranoid value covers a local user who can create severe memory pressure while a PAC1934 probe occurs, although precise control of this small allocation failure is difficult. No supported UAF, information leak, OOB write into a valid object, or privilege escalation path is established. Automated impact decision path. The original SimpleNet classifier selected MODERATE. The primary LLM estimated paranoid CVSS 4.7 and the production ActionableScore returned 1 with recommendation Ordinary Moderate. The production rules then evaluated CVSS thresholds and ActionableScore thresholds. Recorded rule transitions were CVSS and initial triage stage MODERATE to LOW because the CVSS score, vector or bug class threshold rule was applied. The legacy KP specialist has no review artifact for this run. The legacy FD or DH downgrade specialist has no review artifact for this run. Exact triggered rule markers were DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_GUESSCVSS_AND_CIANNH. The independent weaker Aegis shadow evaluated CVSS 2.1 and ActionableScore 1 with primitive class CLASS_C and manual review REQUIRED. Its independently reconciled impact was LOW. The shadow agreed with the final production impact and aggregation did not change that impact. The final reported impact is LOW.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 1)	MAYBE	INIT NOMEMCHK SIMPLEFIX LINUS  DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_GUESSCVSS_AND_CIANNH	-	-	checked

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

ActionableScore=1
PrimitiveClass=CLASS_C
RealUAF=NO
HostAdminRequired=UNKNOWN
NamespaceScopedPrivilege=UNKNOWN
ImportantCandidate=NO
ManualReview=NO
AutoDowngradeAllowed=YES
RequiresHostUID0=UNKNOWN
AuthorizationDecisionBypass=NO
ProtectedResourceImpact=NONE
B4PendingReview=NO
B4PendingConfirmed=NO

1. ActionableScore

* Raw base score: 1.
* Conservative score: 1; no floor or cap applied.
* Raw paranoid score: 1.
* Paranoid score: 1; no additional technically supported primitive.
* Final recommended bucket: **Ordinary Moderate**::

2. Signal breakdown

* +1 Reliable kernel crash/strong DoS: if `devm_kmemdup()` fails, the following terminating-byte store dereferences `NULL + string.length`, plausibly causing an Oops or panic under panic-on-Oops.
* +0 Weak corrupt concern: this is an invalid-address write, not a confirmed heap OOB write into a live allocation.
* No local-unprivileged bonus: memory pressure may influence allocation failure, but userspace control over the required PAC1934 probe/reprobe sequence is not shown.
* No hardware penalty: PAC1934/ACPI presence is required, but the evidence does not establish the “rare physical access” conditions needed for a numeric penalty.
* No C/I, UAF, controlled target, valid-object overwrite, authorization bypass, or privilege-escalation signal.
* NEW52 B5-R does not apply: there is no retry-accumulated index or confirmed heap OOB write followed by corrupted-state consumption.

3. Reachability analysis

The fault requires PAC1934 ACPI parsing during device probing and failure of a small managed allocation. A local user might contribute memory pressure, but cannot be shown to initiate the complete probe path. Conversely, host-admin-only triggering is not positively established, so both host-admin and UID-0 requirements remain unknown. No namespace-scoped capability path, prior delegation, or race is demonstrated.

4. Primitive and severity reading

The exact primitive is a terminating-byte write through a failed allocation result. It is neither active structured-state corruption nor stale storage: the expected outcome is an immediate invalid-address fault. There is no later consumer of corrupted state. This supports CLASS_C crash behavior, not CLASS_A/B corruption. Important review preservation and B4 authorization review are inapplicable; automatic downgrade is safe.

5. One-sentence report phrase

Unchecked `devm_kmemdup()` failure during PAC1934 ACPI probing can cause a NULL-derived terminating-byte write and kernel Oops.

6. Manual review advice

NO MANUAL CHECK NEEDED

The patch directly establishes a constrained allocation-failure crash without a material unresolved corruption or trust-boundary primitive.

7. Call-site confidence

Call-site confidence: high

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

Patch: iio: adc: pac1934: check ACPI label duplication
Commit: b7ac07d0b1a44bf644733298e80fd1f22e2f0cc1
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=b7ac07d0b1a44bf644733298e80fd1f22e2f0cc1

Commit description:

A label duplication failure currently reaches the terminating-byte
write. Release the ACPI result and abort before accessing the missing
label; earlier labels are managed by devres.

Detected by static analysis and reviewed with AI-assisted source auditing.

Fixes: 0fb528c ("iio: adc: adding support for PAC193x")
Assisted-by: LLM
Signed-off-by: Slavin Liu <bolin.liu@seu.edu.cn>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <jonathan.cameron@oss.qualcomm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Changed files:
  drivers/iio/adc/pac1934.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=b7ac07d0b1a44bf644733298e80fd1f22e2f0cc1

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

The original Linux kernel CVE announcement for CVE-2026-98673 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98673

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:L/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS score: 4.7

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: unknown
  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).