[CVE-2026-74294][MODERATE REGULAR] ASoC: meson: aiu: Validate written enum values [ Upstream

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

CVE: CVE-2026-74294
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: ASoC: meson: aiu: Validate written enum values [ Upstream
Commit: 0965892cc486ca554d72eeb62d85ccf8d0137a5a
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=0965892cc486ca554d72eeb62d85ccf8d0137a5a
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74294
Analysis date: Sun, 16 Aug 2026 01:55:03 -0400
ActionableScore: 3
ActionableScore lower bound: 1
Actionable bucket: Borderline, manual review recommended
Manual review required: YES

Summary:
ASoC Meson AIU mux controls validate a userspace enum value too late, allowing a local process with ALSA control access to supply an out-of-range item that may cause a limited out-of-bounds read or unintended mux programming, with impact mainly limited to local device disruption.

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ABOUT THIS REPORT
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The original Linux kernel CVE announcement for CVE-2026-74294 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74294

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.

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AL-KERNEL CLASSIFICATION RESULT
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CVE-2026-74294	MODERATE	CHECK WITH IMPACT FROM ORIG NN LOW	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L';CWE-129;CWE-125;*CWE-20;Other CVSS 'AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '5.3';DESCR 'ASoC meson AIU mux controls used a userspace supplied enum item before validating that it was within the enum item count. A local process with access to the ALSA control device may provide an out-of-range item and cause snd_soc_enum_item_to_val() to read or compute a value outside the intended enumeration. For the CVSS the PR:L is used because triggering requires local access to the sound control interface, often through normal audio device permissions or an audio group rather than full administrator privileges. The issue is not network reachable and is specific to systems using the affected Meson AIU audio controls. Impact is primarily local denial of service or incorrect device state, with limited confidentiality or integrity impact kept only for the paranoid score because the bug class includes an out-of-bounds read from a user controlled index.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline, manual review recommended (with actual score 2)  SKIP CVE-2026-74294 UNKNOWN SKIP No affected files built, so skip this CVE NO  - - unknown 	MAYBE	OOB SIMPLEFIX HARDWARE  DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH	-	-	checked

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ACTIONABLESCORE ANALYSIS
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ActionableScore=3
ActionableScoreLower=1

## 1. ActionableScore

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

## 2. Signal breakdown

Conservative signals:

* Local unprivileged trigger: +1. A local process with access to the ALSA control device can write enum values through the sound control interface.
* Weak corruption or read-only OOB class: +0. The patch shows an out-of-range enum index used before validation, but no OOB write, UAF, double-free, refcount misuse, callback control, or attacker-controlled overwrite primitive.
* Availability impact realistic: +1. Invalid mux values or an invalid read may cause incorrect audio device state or local device disruption.
* Rare and device-specific exposure: -1. The affected path is limited to Meson AIU ASoC controls on systems exposing these controls.

Paranoid additional signals:

* Memory corruption, weak or indirect corruption candidate: +1. The unchecked enum index may be used by `snd_soc_enum_item_to_val()` to read outside the intended enum value table or compute an unintended mux value.
* Integrity impact plausible: +1. The resulting mux value is used in register update logic, so incorrect hardware state or unintended audio routing is plausible.
* Availability impact realistic: +1. A sufficiently bad index may cause device malfunction or possibly a local kernel fault, but this is not shown as a reliable crash in the patch.

Not awarded:

* Remote reachable: +0. No network path.
* Strong LPE plausibility: +0. No reclaim, write primitive, type confusion, stale callback, or object replacement.
* Generic strong memory corruption: +0. This is not an OOB write or UAF.
* High-control device API bonus: +0. ALSA control configuration alone does not show control over kernel object lifetime, layout, DMA mappings, callbacks, or refcounts.
* Confidentiality impact: +0. OOB read is not shown to be disclosed back to userspace.

## 3. Reachability analysis

The likely trigger is a local userspace write to an ALSA mixer/control enum for the affected Meson AIU HDMI or internal codec mux. In many systems, sound controls may be accessible to users in an audio group or to desktop/session services, so PR:L is more appropriate than PR:H for practical triage. Namespaces do not materially improve reachability unless the audio device node is passed into a container. The bug is not default-reachable on generic Linux systems because it depends on Meson AIU hardware and the affected ASoC driver being present and exposed.

Call-site confidence: medium. The changed callbacks and immediate use of the user supplied enum value are visible, but the exact `soc_enum` definitions and whether `e->values` is present for these controls are not included in the provided diff.

## 4. Severity interpretation

This behaves more like a low-end ordinary Moderate or borderline manual-review issue, not an Important-class vulnerability. The theoretical concern is a local user-controlled out-of-range index before validation, which can become a limited OOB read or unintended mux value. The realistic evidence supports local device misconfiguration or limited DoS, not privilege escalation or arbitrary kernel memory corruption. The paranoid score is kept at 3 to avoid auto-closing without confirming the enum table layout and device-node permissions.

## 5. One-sentence report phrase

ASoC Meson AIU mux controls validate a userspace enum value too late, allowing a local process with ALSA control access to supply an out-of-range item that may cause a limited out-of-bounds read or unintended mux programming, with impact mainly limited to local device disruption.

## 6. Manual review recommendation

MANUAL CHECK RECOMMENDED

Reason: the score is low, but the patch fixes a user-controlled index used before validation in kernel code. Manual review should confirm whether these specific controls use an enum value table, whether any OOB value can be disclosed or fault reliably, and what permissions normally protect the affected ALSA control device.

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

Patch: ASoC: meson: aiu: Validate written enum values [ Upstream
Commit: 0965892cc486ca554d72eeb62d85ccf8d0137a5a
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=0965892cc486ca554d72eeb62d85ccf8d0137a5a

Changed files:
  sound/soc/meson/aiu-acodec-ctrl.c
  sound/soc/meson/aiu-codec-ctrl.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=0965892cc486ca554d72eeb62d85ccf8d0137a5a

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

The original Linux kernel CVE announcement for CVE-2026-74294 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74294

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:L/PR:L/UI:N/S:U/C:N/I:N/A:L
  The Best / paranoid CVSS vector: AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
  The Best / paranoid CVSS score: 5.3

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).