[CVE-2026-98940][LOW] ASoC: qcom: lpass-cpu: use DAI table index for playback constraints

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

CVE: CVE-2026-98940
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: ASoC: qcom: lpass-cpu: use DAI table index for playback constraints
Commit: 775df6a27e8433e2414124472938009b958f9a77
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=775df6a27e8433e2414124472938009b958f9a77
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98940
Analysis date: Mon, 26 Oct 2026 21:47:39 -0400
ActionableScore: 2
ActionableScore lower bound: unknown
Actionable bucket: Ordinary Moderate
Manual review required: YES

Summary:
A sparse hardware DAI ID causes two fixed-value writes beyond the allocated DAI driver table during platform probe, with plausible crash impact but no proven low-privilege trigger or exploitable adjacent-state consumer.

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

The original Linux kernel CVE announcement for CVE-2026-98940 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98940

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: YES

A detailed explanation of the methodology and priority rules is included
at the end of this message.

======================================================================
AL-KERNEL CLASSIFICATION RESULT
======================================================================

CVE-2026-98940	LOW	https://www.kernelcve.org/list/?q=CVE-2026-98940 CHECK WITH IMPACT FROM ORIG NN LOW | AEGIS IMPACT MODERATE_KPANIC AEGIS_AS=1 LEGACY=LOW RESULT=DIFF TEMP_DISTANCE_MERGE_SKIP=AEGIS_NO_POSITIVE_SEVERITY_EVIDENCE (final Legacy and Aegis differ; FINAL: LOW, Aegis: MODERATE_KPANIC)	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H';*CWE-787;CWE-129;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:L/A:H';BEST CVSS score: '6.4';DESCR 'A concrete out of bounds kernel write occurs during LPASS CPU platform probe because a sparse hardware DAI ID is incorrectly used as an index into variant dai_driver. On IPQ806x the only MI2S table entry can have DAI ID 4, causing two fixed value writes through dai_driver 4 beyond the single valid entry when QUAD01 mode is selected. For the CVSS the PR:H value reflects that reliable triggering normally requires control of platform configuration, Device Tree, driver loading, or device reprobe. The demonstrated primitive can corrupt adjacent kernel data and cause a crash or integrity failure, while broader confidentiality impact or privilege escalation remains a worst case interpretation that depends on the affected memory layout. Automated impact decision path. The original SimpleNet classifier selected LOW. The primary LLM estimated paranoid CVSS 6.4 and the production ActionableScore returned 2 with recommendation Ordinary Moderate. The production rules then evaluated CVSS thresholds and ActionableScore thresholds. Recorded rule transitions were final reconciliation stage LOW to LOW because KP specialist did not establish a qualifying panic and the cross model evidence reconciliation 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 KPANIC_UNSUPPORTED_REMOVED and V64_AEGIS_UNSUPPORTED_PROMOTION_BLOCKED. The independent weaker Aegis shadow evaluated CVSS 3.0 and ActionableScore 1 with primitive class CLASS_B and manual review REQUIRED. Its independently reconciled impact was MODERATE_KPANIC. The models disagreed but the aggregation rules retained the production result. The final reported impact is LOW.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 2)	MAYBE	SIMPLEFIX HARDWARE KPANIC_UNSUPPORTED_REMOVED V64_AEGIS_UNSUPPORTED_PROMOTION_BLOCKED	-	-	checked

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

ActionableScore=2
PrimitiveClass=CLASS_B
RealUAF=NO
HostAdminRequired=UNKNOWN
NamespaceScopedPrivilege=UNKNOWN
ImportantCandidate=NO
ManualReview=REQUIRED
AutoDowngradeAllowed=YES
RequiresHostUID0=UNKNOWN
AuthorizationDecisionBypass=NO
ProtectedResourceImpact=NONE
B4PendingReview=NO
B4PendingConfirmed=NO

1. ActionableScore

* Raw base score: 2.
* Conservative score: 2; no floor or cap applied.
* Raw paranoid score: 2.
* Paranoid score: 2; stronger impact would require unsupported reachability or downstream-consumer assumptions.
* Final recommended bucket: **Ordinary Moderate**::

2. Signal breakdown

* +1 constrained kernel buffer overwrite: two fixed assignments write `channels_min` and `channels_max` through `dai_driver[dai_id]`; on the described one-entry IPQ806x table, ID 4 is out of bounds.
* +1 plausible kernel crash/strong DoS: corrupting adjacent heap/slab storage during probe can plausibly fault or destabilize the kernel. No separate Availability point is added.
* No privilege penalty: platform configuration, Device Tree control, driver loading, or reprobe are suggested, but host-admin-only triggering is not positively established.
* No Class-A bonus: payloads are fixed values, the offset is hardware-ID-derived, and neither an attacker-selected target nor a named adjacent object is shown.
* NEW52/B5-R does not apply: there is no retry-accumulated index, attacker-influenced retry sequence, or proven later consumption of corrupted structured state.
* Controlled reclaim, arbitrary write, disclosure, LPE, authorization bypass, and cross-boundary corruption are not shown.

3. Reachability analysis

The write occurs during LPASS platform probe on a sparse-DAI platform with QUAD01 selected. The supplied evidence does not establish a normal-user, delegated-service, or namespace-scoped interface capable of arranging the complete trigger. Host Device Tree or platform configuration may require administrator control, but “normally requires” is insufficient to mark `HostAdminRequired=YES`. No race, retry loop, prior namespace setup, or remotely reachable path is shown.

4. Primitive and severity reading

The exact primitive is a fixed-width heap/slab OOB write to two integer fields beyond the DAI driver array. It is not a UAF or repeated lifetime mutation. The adjacent object and any later consumer are unidentified, so this is constrained CLASS_B corruption rather than CLASS_A controlled corruption. Crash or integrity failure is plausible; useful corruption, confidentiality loss, and privilege escalation remain unproven. ImportantCandidate is NO because attacker-invocable reachability and active corrupted-state consumption are both missing. Auto-downgrade remains allowed, although manual validation of allocation layout and probe reachability is required.

5. One-sentence report phrase

A sparse hardware DAI ID causes two fixed-value writes beyond the allocated DAI driver table during platform probe, with plausible crash impact but no proven low-privilege trigger or exploitable adjacent-state consumer.

6. Manual review advice

MANUAL CHECK REQUIRED

Confirm the concrete allocation layout, affected platforms, trigger privileges, and whether the overwritten adjacent state is subsequently consumed.

7. Call-site confidence

Call-site confidence: medium

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

Patch: ASoC: qcom: lpass-cpu: use DAI table index for playback constraints
Commit: 775df6a27e8433e2414124472938009b958f9a77
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=775df6a27e8433e2414124472938009b958f9a77

Commit description:

The DAI ID is a hardware port ID and is not necessarily the index of
the corresponding entry in variant->dai_driver.

When configuring a DAI with LPAIF_I2SCTL_MODE_QUAD01, the probe code
currently uses dai_id to index variant->dai_driver. This is incorrect
for platforms where DAI IDs are sparse. For example, the IPQ806x MI2S
DAI has ID 4 while it is the only entry in the DAI driver table. If
that DAI is configured for QUAD01 and probe reaches this branch, the
code writes beyond that single entry via dai_driver[4] instead of
updating the DAI being processed.

Use the loop index i when updating the current DAI's playback channel
constraints, while retaining dai_id for indexing the hardware-port
specific playback SD-line mode array.

This fixes the incorrect DAI table access for platforms where the DAI
ID does not match its position in the driver table.

Fixes: c223f41 ("ASoC: qcom: Add four speaker support on MI2S secondary")
Cc: stable@vger.kernel.org
Signed-off-by: Zimeng Li <me@lizi.moe>
Assisted-by: LLM-assisted source analysis
Reviewed-by: Srinivas Kandagatla <srinivas.kandagatla@oss.qualcomm.com>
Link: https://patch.msgid.link/20260927010911.51980-1-me@lizi.moe
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Changed files:
  sound/soc/qcom/lpass-cpu.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=775df6a27e8433e2414124472938009b958f9a77

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

The original Linux kernel CVE announcement for CVE-2026-98940 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98940

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:L/A:H
  The Best / paranoid CVSS vector: AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
  The Best / paranoid CVSS score: 6.4

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: unknown
  Paranoid ActionableScore: 2

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).