[CVE-2026-74291][MODERATE REGULAR] ASoC: topology: Check PCM and DAI name strings before use [ Upstream

[CVE-2026-74291][MODERATE REGULAR] ASoC: topology: Check PCM and DAI name strings before use [ Upstream

[AL-KERNEL]

CVE: CVE-2026-74291
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: ASoC: topology: Check PCM and DAI name strings before use [ Upstream
Commit: ba37b62ed0a443b8e23f53a7477e7f2537fd34c7
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=ba37b62ed0a443b8e23f53a7477e7f2537fd34c7
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74291
Analysis date: Sat, 15 Aug 2026 22:57:57 -0400
ActionableScore: 3
ActionableScore lower bound: 0
Actionable bucket: Borderline manual review recommended / Ordinary Moderate in typical deployments
Manual review required: YES

Summary:
A malformed ASoC topology blob can provide non-NUL-terminated PCM or DAI name fields, causing the kernel topology parser to read past fixed-size UAPI arrays and potentially leak adjacent data or crash during local topology parsing.

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

The original Linux kernel CVE announcement for CVE-2026-74291 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74291

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

CVE-2026-74291	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:N/A:L';CWE-125;CWE-170;*CWE-20;Other CVSS 'AV:L/AC:L/PR:H/UI:N/S:U/C:L/I:N/A:L';BEST CVSS score: '4.4';DESCR 'ASoC topology parsing can read past fixed size UAPI name fields because PCM, DAI, and stream capability names may be used as C strings without first proving that they are NUL terminated. A malformed topology blob can therefore make strlen, devm_kstrdup, DAI lookup, or diagnostic paths consume bytes beyond the intended field boundary. For the CVSS the PR:L in the paranoid score reflects environments where a non admin local process can influence topology data through a delegated audio management service, firmware update path, or similar local mechanism. The issue is not network reachable and requires local ability to affect the topology blob consumed by the kernel. Impact is mainly limited information disclosure or denial of service through an out of bounds read, with no supported evidence of memory corruption or privilege escalation.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline manual review recommended / Ordinary Moderate in typical deployments (with actual score 2)	YES	HARDWARE  INCREASED_FROM_LOW_BASED_ON_REQUIREMANUALCHECK DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN5	NO	NO	checked

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

ActionableScore=3
ActionableScoreLower=0

## 1. ActionableScore

* Conservative score: 0
* Paranoid score: 3
* Final recommended bucket: **Borderline manual review recommended / Ordinary Moderate in typical deployments**

## 2. Signal breakdown

Conservative signals:

* Requires admin/root/CAP in typical deployments: -2. Supplying or replacing ASoC topology blobs is normally controlled by firmware loading, platform integration, or privileged audio/device setup.
* Confidentiality impact plausible: +1. A non-NUL-terminated fixed-size name can make strlen() or devm_kstrdup() read beyond the intended field, and copied or printed strings could expose adjacent kernel/topology data.
* Availability impact realistic: +1. An unbounded C-string read past the fixed field can plausibly cause parser failure, excessive read/copy, warning, or crash depending on allocation layout.
* Rare AND difficult-to-reach subsystem/configuration: -1. ASoC topology parsing is relevant mostly to systems using ALSA SoC topology firmware blobs, not broad server/default kernel exposure.

Paranoid signals:

* Local unprivileged trigger: +1. Applies only if a non-admin local actor can influence topology data through a delegated audio management service, firmware update path, containerized device service, or misconfiguration.
* Confidentiality impact plausible: +1. The primitive is an OOB read from adjacent memory while treating fixed UAPI arrays as C strings.
* Availability impact realistic: +1. Malformed topology data can plausibly crash or disrupt kernel-side topology parsing.
* No generic memory corruption bonus. The patch shows read past end only, not OOB write, UAF, double free, type confusion, or attacker-controlled overwrite.
* No LPE bonus. There is no supported privilege escalation primitive beyond limited OOB read and possible DoS.

Call-site confidence: high. The patch shows the affected call sites directly: strlen(), devm_kstrdup(), DAI lookup, and stream/link name handling.

## 3. Reachability analysis

The bug is triggered by a malformed ASoC topology blob containing PCM, DAI, or stream capability names that are not NUL terminated inside the fixed-size UAPI field. In typical deployments, topology blobs are loaded from firmware or privileged system configuration, so the conservative model treats this as privileged local reachability. Namespaces do not normally make this unprivileged unless a container or service is explicitly allowed to supply topology data to the host kernel. The path is not network reachable. Realistic exploitation requires access to the topology blob input path on an affected audio platform.

## 4. Severity interpretation

This behaves like an ordinary Moderate or Low-like issue in default deployments because the trigger is usually privileged and the primitive is limited OOB read. The paranoid interpretation is still worth manual review because kernel parsers copying unterminated strings can sometimes expose adjacent data or crash depending on memory layout. There is no evidence of write corruption, object lifetime corruption, or practical privilege escalation.

## 5. One-sentence report phrase

A malformed ASoC topology blob can provide non-NUL-terminated PCM or DAI name fields, causing the kernel topology parser to read past fixed-size UAPI arrays and potentially leak adjacent data or crash during local topology parsing.

## 6. Manual review recommendation

MANUAL CHECK REQUIRED

Reason: the score is not Important-class, but this is a kernel OOB read in a parser for externally supplied topology data, and the real impact depends on who can provide topology blobs and whether the over-read can reach user-visible diagnostic or duplicated string paths.

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

Patch: ASoC: topology: Check PCM and DAI name strings before use [ Upstream
Commit: ba37b62ed0a443b8e23f53a7477e7f2537fd34c7
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=ba37b62ed0a443b8e23f53a7477e7f2537fd34c7

Changed files:
  sound/soc/soc-topology.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=ba37b62ed0a443b8e23f53a7477e7f2537fd34c7

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

The original Linux kernel CVE announcement for CVE-2026-74291 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74291

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:H/UI:N/S:U/C:L/I:N/A:L
  The Best / paranoid CVSS vector: AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:L
  The Best / paranoid CVSS score: 4.4

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: 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).