[CVE-2026-74293][MODERATE REGULAR] ASoC: fsl: fsl_audmix: Validate written enum values [ Upstream

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

CVE: CVE-2026-74293
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: ASoC: fsl: fsl_audmix: Validate written enum values [ Upstream
Commit: 7513831b90a38d55fa089e3e1b49691e467afee6
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=7513831b90a38d55fa089e3e1b49691e467afee6
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74293
Analysis date: Sat, 15 Aug 2026 07:14:25 -0400
ActionableScore: 3
ActionableScore lower bound: 2
Actionable bucket: Borderline, manual review recommended
Manual review required: YES

Summary:
A local user with access to the affected ALSA mixer controls can provide an out-of-range enum value that is used before validation in fsl_audmix, causing OOB read or invalid table indexing with likely impact limited to local DoS or incorrect audio device state.

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

The original Linux kernel CVE announcement for CVE-2026-74293 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74293

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-2026-74293	MODERATE	CHECK WITH IMPACT FROM ORIG NN MODERATE	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H';CWE-129;CWE-125;*CWE-20;Other CVSS 'AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L';BEST CVSS score: '5.5';DESCR 'ASoC fsl_audmix accepts a user controlled ALSA enum item and used it before validating that the item is within the enum item count. An out-of-range value can be converted by snd_soc_enum_item_to_val() and then used in BIT() logic or as an index into the output source transition table, which creates an OOB read or invalid table indexing condition in the kernel. For the CVSS the PR:L is selected because triggering requires a local user or process with permission to write the affected ALSA mixer controls, not full administrator privileges. The issue is not network reachable and depends on systems that use the Freescale fsl_audmix ASoC driver. Impact is primarily local denial of service or incorrect audio hardware state, with no strong evidence of arbitrary write or privilege escalation.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline, manual review recommended (with actual score 3)  SKIP CVE-2026-74293 UNKNOWN SKIP No affected files built, so skip this CVE NO  - - unknown 	MAYBE	OOB SIMPLEFIX HARDWARE TEST 	-	-	checked

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ACTIONABLESCORE ANALYSIS
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ActionableScore=3
ActionableScoreLower=2

## 1. ActionableScore

* Conservative score: 2
* Paranoid score: 3
* Final recommended bucket: **Borderline, manual review recommended**::

## 2. Signal breakdown

* Local unprivileged trigger: +1
  A local process that can write the affected ALSA mixer controls may provide an out-of-range enum item. This is not a remote path.

* Memory corruption, weak or indirect candidate: +1
  The bug is an unchecked enum index before conversion. The result may cause OOB read or invalid table indexing, but the patch does not show OOB write, UAF, double free, controlled overwrite, or callback corruption.

* Availability impact plausible: +1 in paranoid score only
  Invalid kernel table indexing or invalid derived register state may plausibly crash or destabilize the driver, but no concrete panic trace or reliable crash path is shown.

* Rare AND difficult-to-reach subsystem/configuration: -1 in conservative score
  This affects the Freescale fsl_audmix ASoC driver and requires the relevant hardware and ALSA controls to be exposed.

Not awarded:

* No remote reachable signal.
* No strong memory corruption primitive.
* No Dirty-Pipe-like ownership or COW bypass.
* No demonstrated privilege escalation.
* No confidentiality impact.
* No high-control API bonus. ALSA control writes configure device state but the patch does not show control over memory layout, lifetime, refcounts, DMA mappings, or callbacks.

Call-site confidence: medium. The affected callbacks and immediate misuse are visible, but broader table definitions and all hardware side effects are not included.

## 3. Reachability analysis

The trigger is local through ALSA SoC mixer control writes. In typical systems, access depends on device node and mixer-control permissions, often limited to audio-session users, audio group members, or privileged services. Namespaces do not obviously make this remotely reachable. The path is not default-exposed on most generic servers because it depends on Freescale fsl_audmix hardware and driver configuration.

## 4. Severity interpretation

This behaves more like a borderline Moderate issue than an Important-class vulnerability. The theoretical concern is kernel OOB read or invalid table indexing from a user-controlled enum value. Realistic evidence supports local DoS or incorrect device state more than privilege escalation. The patch is a validation fix and does not demonstrate attacker-controlled overwrite, object lifetime corruption, type confusion, or an LPE primitive.

## 5. One-sentence report phrase

A local user with access to the affected ALSA mixer controls can provide an out-of-range enum value that is used before validation in fsl_audmix, causing OOB read or invalid table indexing with likely impact limited to local DoS or incorrect audio device state.

## 6. Manual review recommendation

MANUAL CHECK RECOMMENDED

Reason: this is not a simple resource leak or warning-only fix. It is user-controlled bounds validation before kernel array-related operations, but the available patch does not support Important-class scoring without more evidence of a write primitive, reliable crash, or privilege-escalation path.

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

Patch: ASoC: fsl: fsl_audmix: Validate written enum values [ Upstream
Commit: 7513831b90a38d55fa089e3e1b49691e467afee6
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=7513831b90a38d55fa089e3e1b49691e467afee6

Changed files:
  sound/soc/fsl/fsl_audmix.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=7513831b90a38d55fa089e3e1b49691e467afee6

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

The original Linux kernel CVE announcement for CVE-2026-74293 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74293

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:L/A:L
  The Best / paranoid CVSS vector: AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS score: 5.5

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: 2
  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).