[CVE-2026-74333][MODERATE REGULAR] ASoC: amd: acp-sdw-legacy: Bound DAI link iteration [ Upstream

[CVE-2026-74333][MODERATE REGULAR] ASoC: amd: acp-sdw-legacy: Bound DAI link iteration [ Upstream

[AL-KERNEL]

CVE: CVE-2026-74333
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: ASoC: amd: acp-sdw-legacy: Bound DAI link iteration [ Upstream
Commit: 1279bdab5fa1f28c168e54215db506e87c6fac1e
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=1279bdab5fa1f28c168e54215db506e87c6fac1e
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74333
Analysis date: Sat, 15 Aug 2026 11:44:25 -0400
ActionableScore: 3
ActionableScore lower bound: 1
Actionable bucket: Ordinary Moderate / Borderline manual review
Manual review required: NO

Summary:
An AMD ACP SoundWire legacy ASoC probe path can read past the end of the `soc_dais` array during DAI link creation, causing a KASAN-detected slab out-of-bounds read and possible local DoS on affected hardware configurations.

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ABOUT THIS REPORT
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The original Linux kernel CVE announcement for CVE-2026-74333 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74333

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: 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-2026-74333	MODERATE	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:N/A:H';CWE-125;CWE-129;CWE-193;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '5.3';DESCR 'ASoC AMD acp sdw legacy machine driver can read past the end of the soc_dais array during SoundWire DAI link creation. The loop used the initialised field as a sentinel, but the array is allocated with exactly num_ends entries and may not contain a terminating entry. If all entries are initialised, mc_probe can perform a slab out of bounds read and may crash the kernel or fail device probing. For the CVSS the PR:L is used for the paranoid score because reliable attacker driven triggering would normally require local control over driver reprobe, module load, or delegated device management rather than network access. The issue is not network reachable and depends on a specific AMD SoundWire legacy audio configuration. Impact is mainly denial of service, with limited confidentiality concern only in the paranoid score because the primitive is an invalid kernel read rather than an overwrite or UAF.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Borderline manual review (with actual score 2)	YES	READ KASAN OOB INIT SIMPLEFIX HARDWARE  DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH	YES	NO	checked

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

ActionableScore=3
ActionableScoreLower=1

## 1. ActionableScore

* Conservative score: 1
* Paranoid score: 3
* Final recommended bucket: **Ordinary Moderate / Borderline manual review**

## 2. Signal breakdown

Conservative signals:

* Weak memory corruption candidate: +1. The patch fixes a bounded iteration bug where `soc_dais->initialised` can be read past the end of the allocated `soc_dais` array.
* Requires admin/root/device-management control in typical deployments: -2. Reliable attacker-driven triggering normally requires driver reprobe, module reload, or platform device management.
* Rare hardware/configuration dependency: -1. The affected path is specific to AMD ACP SoundWire legacy machine driver probing.
* Availability impact possible: +1. KASAN reports slab-out-of-bounds during `mc_probe`, and this can plausibly fail probe or crash in debug/panic configurations.

Paranoid signals:

* Weak memory corruption candidate: +1. This is a confirmed kernel slab out-of-bounds read, but only read size 1 and no write/UAF/reclaim primitive is shown.
* Reliable kernel crash / strong DoS concern: +1. KASAN shows a concrete OOB access in kernel probe code.
* Local lower-privilege trigger concern: +1. In environments with delegated device management, module autoload side effects, or containerized device control, PR may be lower than full host root.
* Confidentiality impact plausible: +1. Limited OOB read exists, but no user-visible disclosure path is shown.
* Rare hardware/configuration dependency: -1. Exposure depends on a specific AMD SoundWire legacy audio configuration.

No LPE bonus is awarded. The patch shows an out-of-bounds read, not UAF, OOB write, object replacement, callback control, refcount abuse, or attacker-controlled reclaim.

## 3. Reachability analysis

The bug is reached during SoundWire DAI link creation in the AMD ACP SoundWire legacy ASoC machine driver, specifically during probe/setup. It is not network reachable and is not a general local syscall or packet-processing path. In normal deployments, reliable triggering likely requires affected hardware plus privileged control over driver loading, reprobe, or platform device lifecycle. Namespace/container impact is limited unless device-management capabilities are delegated to less trusted users.

## 4. Severity interpretation

This behaves more like an ordinary Moderate issue with a borderline manual-review reason. Theoretical memory-safety impact exists because KASAN confirms a slab out-of-bounds read, but realistic exploitation evidence points mainly to probe failure or kernel crash, not privilege escalation. The read is very constrained and no write primitive, UAF, stale pointer reuse, type confusion, or attacker-controlled disclosure path is demonstrated.

## 5. One-sentence report phrase

An AMD ACP SoundWire legacy ASoC probe path can read past the end of the `soc_dais` array during DAI link creation, causing a KASAN-detected slab out-of-bounds read and possible local DoS on affected hardware configurations.

## 6. Manual review recommendation

MANUAL CHECK RECOMMENDED

Reason: confirmed kernel OOB read in probe code, but constrained primitive and hardware-specific reachability make it unlikely to be Important without additional evidence.

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

Patch: ASoC: amd: acp-sdw-legacy: Bound DAI link iteration [ Upstream
Commit: 1279bdab5fa1f28c168e54215db506e87c6fac1e
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=1279bdab5fa1f28c168e54215db506e87c6fac1e

Changed files:
  sound/soc/amd/acp/acp-sdw-legacy-mach.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=1279bdab5fa1f28c168e54215db506e87c6fac1e

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

The original Linux kernel CVE announcement for CVE-2026-74333 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74333

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