[CVE-2026-46262][LOW] ASoC: fsl_xcvr: Revert fix missing lock in fsl_xcvr_mode_put() [ Upstream

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

CVE: CVE-2026-46262
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: ASoC: fsl_xcvr: Revert fix missing lock in fsl_xcvr_mode_put() [ Upstream
Commit: ae5a70e3e87c28edbaf9939cfef1bcbd9615420f
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=ae5a70e3e87c28edbaf9939cfef1bcbd9615420f
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-46262
Analysis date: Wed, 03 Jun 2026 15:54:27 -0400
ActionableScore: 2
ActionableScore lower bound: 1
Actionable bucket: Ordinary Moderate / Low-like
Manual review required: NO

Summary:
A local ALSA control write in the ASoC fsl_xcvr driver can deadlock because `fsl_xcvr_mode_put()` re-acquires `controls_rwsem` while the ALSA core already holds it, causing a hung task and local denial of service on affected hardware.

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ABOUT THIS REPORT
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The original Linux kernel CVE announcement for CVE-2026-46262 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-46262

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-2026-46262	LOW	CHECK	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-667;*CWE-833;CWE-662;Other CVSS 'AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '5.5';DESCR 'A local deadlock can occur in the ASoC fsl_xcvr control path because fsl_xcvr_mode_put() tried to take controls_rwsem for read while snd_ctl_elem_write() already holds the same rwsem for write during the full put operation. This can hang the calling task and block ALSA control handling for the affected sound card, causing a local denial of service rather than memory corruption. For the CVSS the PR:L is used because a local process with access to the ALSA control device is needed to write the affected control. The issue is not network reachable. Impact is availability only. No confidentiality or integrity impact is justified because the patch shows a locking deadlock and not a UAF, OOB access, info leak, or write primitive.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 2) 	MAYBE	WRITE OOB DEADLOCK 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

* Local unprivileged trigger: +1. A local process with access to the relevant ALSA control device may trigger the affected put callback.
* Reliable kernel crash / strong DoS: +1 in paranoid scoring only. The issue causes a self-deadlock and hung task, but not a kernel panic or memory corruption.
* Rare AND difficult-to-reach subsystem/configuration: -1. This is specific to the Freescale fsl_xcvr ASoC driver and requires affected hardware and exposed ALSA controls.
* No memory corruption: +0. The patch removes nested locking only. There is no UAF, double-free, OOB access, overwrite, info leak, or object lifetime corruption.
* No privilege escalation plausibility: +0. The observed primitive is a lock self-deadlock, not a control-flow or data-corruption primitive.
* Availability impact realistic: +0 conservative. The DoS is limited to a hung control operation or affected sound-card control path, not clearly a system-wide crash.

## 3. Reachability analysis

The bug is triggered through a local ALSA control write path reaching `fsl_xcvr_mode_put()`. It is not remotely reachable and is not in a common network or filesystem path. In typical deployments, access depends on device permissions, often root, audio group, or a local desktop/session user. Containers do not materially increase exposure unless the sound device is explicitly passed through. The affected driver and hardware are relatively specific, so broad default exposure is low.

## 4. Severity interpretation

This behaves like a low-end Moderate or Low-like local availability issue. The theoretical impact is a hung task caused by recursive incompatible locking on `controls_rwsem`. Realistic exploitation evidence supports local DoS against the affected ALSA control path only. There is no demonstrated or implied memory corruption, privilege escalation, information disclosure, or cross-boundary security bypass.

## 5. One-sentence report phrase

A local ALSA control write in the ASoC fsl_xcvr driver can deadlock because `fsl_xcvr_mode_put()` re-acquires `controls_rwsem` while the ALSA core already holds it, causing a hung task and local denial of service on affected hardware.

## 6. Manual review recommendation

NO MANUAL CHECK NEEDED

This can be handled as an ordinary low-priority Moderate because it is a device-specific local deadlock with availability-only impact and no memory corruption or privilege escalation primitive.

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

Patch: ASoC: fsl_xcvr: Revert fix missing lock in fsl_xcvr_mode_put() [ Upstream
Commit: ae5a70e3e87c28edbaf9939cfef1bcbd9615420f
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=ae5a70e3e87c28edbaf9939cfef1bcbd9615420f

Changed files:
  sound/5056506.GXAFRqVoOG
  sound/soc/fsl/fsl_xcvr.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=ae5a70e3e87c28edbaf9939cfef1bcbd9615420f

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

The original Linux kernel CVE announcement for CVE-2026-46262 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-46262

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:L
  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).