[CVE-2026-64107][LOW] ASoC: codecs: pcm512x: fix null-ptr dereference in pcm512x_overclock_xxx_put()

[CVE-2026-64107][LOW] ASoC: codecs: pcm512x: fix null-ptr dereference in pcm512x_overclock_xxx_put()

[AL-KERNEL]

CVE: CVE-2026-64107
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: ASoC: codecs: pcm512x: fix null-ptr dereference in pcm512x_overclock_xxx_put()
Commit: 285159ca199cbbe424223d4b14db227b279b5767
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=285159ca199cbbe424223d4b14db227b279b5767
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-64107
Analysis date: Sun, 19 Jul 2026 11:43:49 -0400
ActionableScore: 2
ActionableScore lower bound: 1
Actionable bucket: Ordinary Moderate / Low-like
Manual review required: NO

Summary:
A local NULL pointer dereference in the ASoC pcm512x ALSA mixer control path can crash the kernel when an affected overclock control is written on systems using the pcm512x codec.

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

The original Linux kernel CVE announcement for CVE-2026-64107 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-64107

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: 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-2026-64107	LOW	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-476;CWE-754;CWE-703;BEST CVSS score: '5.5';DESCR 'A NULL pointer dereference can occur in the ASoC pcm512x codec driver because pcm512x_overclock_pll_put, pcm512x_overclock_dsp_put, and pcm512x_overclock_dac_put are general ALSA mixer kcontrol handlers but used a DAPM kcontrol helper to obtain the DAPM context. A local user or local audio service that can write the affected mixer control on a system with the pcm512x codec may trigger a kernel crash. For the CVSS the PR:L is used because triggering requires a local user context with access to the ALSA control interface, but not full administrative privileges in typical desktop or embedded audio deployments. The issue is not network reachable. Impact is denial of service only, with no supported evidence of memory corruption, information disclosure, or privilege escalation.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 2)  SKIP CVE-2026-64107 UNKNOWN SKIP No affected files built, so skip this CVE NO  - - unknown 	MAYBE	NULLPTR SIMPLEFIX HARDWARE  DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3	-	-	checked

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ACTIONABLESCORE ANALYSIS
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ActionableScore=2
ActionableScoreLower=1

## 1. ActionableScore

* Conservative score: 1
* Paranoid score: 2
* Final recommended bucket: **Ordinary Moderate / Low-like**::

## 2. Signal breakdown

Conservative signals:

* Local unprivileged trigger: +1. A local user or local audio service with permission to write the affected ALSA mixer kcontrol may trigger the bug.
* Reliable kernel crash / strong DoS: +1. The commit explicitly describes a NULL pointer dereference in the kcontrol put handler.
* Rare AND difficult-to-reach subsystem/configuration: -1. The issue is limited to systems using the pcm512x codec driver and the affected overclock mixer controls.

Paranoid adjustment:

* Paranoid score does not subtract the hardware-specific exposure as strongly, because pcm512x is used in real embedded and Raspberry Pi audio deployments. This yields ActionableScore=2.

Not applied:

* No generic memory corruption. This is a NULL pointer dereference, not UAF, OOB write, double free, type confusion, or refcount misuse.
* No privilege escalation plausible. The patch does not show attacker-controlled reclaim, overwrite, callback control, stale object reuse, or arbitrary write.
* No confidentiality or integrity impact. The failure mode is a crash only.
* No remote reachable signal. ALSA mixer controls are local control-plane interfaces.

Call-site confidence: high. The affected functions and dereference path are visible in the patch.

## 3. Reachability analysis

The bug is reachable through local ALSA mixer control writes on systems exposing the pcm512x overclock controls. A normal local user may be able to trigger it if audio device permissions allow mixer control access, which is common through desktop or embedded audio policy groups and services. It is not network reachable and does not involve packet parsing, filesystem metadata, page cache ownership, DMA ownership, or cross-namespace security boundaries. Containers only matter if the audio device or ALSA control node is delegated into the container.

## 4. Severity interpretation

This behaves like an ordinary Moderate or Low-like local DoS. The theoretical impact is a kernel crash from a NULL pointer dereference. Realistic exploitation evidence supports denial of service only. There is no supported memory corruption primitive and no plausible LPE path from the provided patch.

## 5. One-sentence report phrase

A local NULL pointer dereference in the ASoC pcm512x ALSA mixer control path can crash the kernel when an affected overclock control is written on systems using the pcm512x codec.

## 6. Manual review recommendation

NO MANUAL CHECK NEEDED.

This is a device-specific local NULL pointer dereference with no evidence of UAF, writable stale object access, object replacement, information disclosure, integrity impact, or privilege escalation.

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

Patch: ASoC: codecs: pcm512x: fix null-ptr dereference in pcm512x_overclock_xxx_put()
Commit: 285159ca199cbbe424223d4b14db227b279b5767
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=285159ca199cbbe424223d4b14db227b279b5767

Commit description:

In the pcm512x chipset driver, pcm512x_overclock_xxx_put() is defined as
a general mixer kcontrol instead of a DAPM kcontrol, so struct
snd_soc_dapm_context must not be accessed via
snd_soc_dapm_kcontrol_to_dapm().

This causes a NULL pointer dereference, so it must be modified to use
snd_soc_component_to_dapm().

Cc: stable@kernel.org
Closes : raspberrypi/linux#7242
Fixes: 02dbbb7 ("ASoC: codecs: pcm512x: convert to snd_soc_dapm_xxx()")
Signed-off-by: Jeongjun Park <aha310510@gmail.com>
Link: https://patch.msgid.link/20260521113712.227438-1-aha310510@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Changed files:
  sound/soc/codecs/pcm512x.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=285159ca199cbbe424223d4b14db227b279b5767

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

The original Linux kernel CVE announcement for CVE-2026-64107 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-64107

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: Not available
  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: 1
  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).