[CVE-2026-64133][MODERATE REGULAR] ALSA: asihpi: Fix potential OOB array access at reading cache

[CVE-2026-64133][MODERATE REGULAR] ALSA: asihpi: Fix potential OOB array access at reading cache

[AL-KERNEL]

CVE: CVE-2026-64133
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: ALSA: asihpi: Fix potential OOB array access at reading cache
Commit: e060e21fe9cca1e5eafd8a1c597026577771e8d9
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=e060e21fe9cca1e5eafd8a1c597026577771e8d9
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-64133
Analysis date: Sun, 19 Jul 2026 13:40:20 -0400
ActionableScore: 3
ActionableScore lower bound: 2
Actionable bucket: Borderline manual review recommended
Manual review required: YES

Summary:
ALSA asihpi `find_control()` used an unchecked control index to read the cached control pointer array, allowing a local user with access to the affected sound device to trigger an OOB read that may cause a kernel crash and warrants manual review.

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ABOUT THIS REPORT
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The original Linux kernel CVE announcement for CVE-2026-64133 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-64133

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-2026-64133	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:H';CWE-125;CWE-129;*CWE-20;Other CVSS 'AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '6.1';DESCR 'An out of bounds read in the ALSA asihpi driver can occur because find_control uses control_index to access the cached p_info array without first checking it against control_count. A local user with access to the affected ALSA control device may be able to request an invalid control index, causing the driver to read past the cached control pointer array and potentially dereference an invalid pointer. For the CVSS the PR:L is used because triggering requires local access to the sound device interface, but not necessarily full administrator privileges. The issue is not network reachable. Impact is at least local denial of service via kernel crash. The paranoid score keeps limited confidentiality impact because the bug class is OOB read, but there is no clear OOB write or UAF primitive in the provided patch context.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline manual review recommended (with actual score 3)	YES	OOB SIMPLEFIX HARDWARE LINUS  DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN5	NO	NO	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 user with access to the affected ALSA control device may be able to provide or reach an invalid control index.
* Memory corruption, weak/indirect corruption candidate: +1. The bug is an unchecked array index into `p_cache->p_info`, producing an OOB read of a cached control pointer.
* Reliable kernel crash / strong DoS: +1 in paranoid only. If the OOB pointer is later dereferenced, this can plausibly lead to kernel oops or crash, but the patch does not show a demonstrated reliable crash path.
* Confidentiality impact plausible: +1 in paranoid only. The primitive is read-side OOB and may expose or misinterpret adjacent pointer data, but no clear user-visible information leak is demonstrated.
* Rare AND difficult-to-reach subsystem/configuration: -1. `snd-asihpi` is a hardware-specific PCI audio driver and is not a broad default attack surface.

## 3. Reachability analysis

Triggering appears local through ALSA/asihpi control paths. It likely requires the affected hardware or module to be present and a user to have access to the corresponding `/dev/snd/controlC*` device. This is not network reachable. Namespaces do not obviously reduce the privilege requirement unless the sound device is explicitly passed into a container. Call-site confidence: medium, because the immediate OOB access is visible, but full caller behavior and user-visible propagation are not included in the provided patch.

## 4. Severity interpretation

This behaves like a borderline Moderate issue rather than an Important-class kernel vulnerability. Theoretical impact includes local DoS and limited read-side confusion from an OOB pointer-array access. Realistic LPE evidence is weak because the patch shows no OOB write, UAF reclaim, type confusion, callback control, refcount abuse, or attacker-controlled object replacement.

## 5. One-sentence report phrase

ALSA asihpi `find_control()` used an unchecked control index to read the cached control pointer array, allowing a local user with access to the affected sound device to trigger an OOB read that may cause a kernel crash and warrants manual review.

## 6. Manual review recommendation

MANUAL CHECK RECOMMENDED. The issue is not broad or remotely reachable, but kernel OOB reads of pointer arrays can sometimes have caller-dependent consequences beyond a simple crash.

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

Patch: ALSA: asihpi: Fix potential OOB array access at reading cache
Commit: e060e21fe9cca1e5eafd8a1c597026577771e8d9
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=e060e21fe9cca1e5eafd8a1c597026577771e8d9

Commit description:

find_control() to retrieve a cached info accesses the array with the
given index blindly, which may lead to an OOB array access.
Add a sanity check for avoiding it.

Link: https://sashiko.dev/#/patchset/20260511230121.28606-1-rosenp%40gmail.com
Cc: <stable@vger.kernel.org>
Link: https://patch.msgid.link/20260515085606.242284-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Changed files:
  sound/pci/asihpi/hpicmn.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=e060e21fe9cca1e5eafd8a1c597026577771e8d9

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

The original Linux kernel CVE announcement for CVE-2026-64133 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-64133

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:H
  The Best / paranoid CVSS vector: AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H
  The Best / paranoid CVSS score: 6.1

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).