[CVE-2026-53100][LOW] wifi: mt76: fix deadlock in remain-on-channel [ Upstream

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

CVE: CVE-2026-53100
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: wifi: mt76: fix deadlock in remain-on-channel [ Upstream
Commit: 5fc8c5d45e44575dda9fcabdc2aac4ad97baf0cd
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=5fc8c5d45e44575dda9fcabdc2aac4ad97baf0cd
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53100
Analysis date: Wed, 24 Jun 2026 15:23:10 -0400
ActionableScore: 1
ActionableScore lower bound: 0
Actionable bucket: Ordinary Moderate / Low-like
Manual review required: NO

Summary:
A local mt76 remain-on-channel operation can deadlock the WiFi driver because mt76_set_channel() is called while dev mutex is already held, causing a device-level denial of service without evidence of memory corruption or privilege escalation.

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

The original Linux kernel CVE announcement for CVE-2026-53100 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53100

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

CVE-2026-53100	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:H/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '5.5';DESCR 'The mt76 remain-on-channel path can deadlock because mt76_remain_on_channel() and mt76_roc_complete() may call mt76_set_channel() while dev mutex is already held, and mt76_set_channel() tries to acquire the same mutex again. This can leave the WiFi driver control path stuck and can make remain-on-channel or recovery operations stop progressing, causing a local denial of service for the wireless device. For the CVSS the PR:L value is used in the paranoid score because an untrusted local actor may be able to trigger remain-on-channel indirectly through delegated WiFi management, a service account, or reduced capability network administration. The issue is not directly network reachable and is triggered through local wireless control plane operations rather than remote packet traffic. Impact is denial of service only, with no evidence of memory corruption, information disclosure, or privilege escalation.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 1) 	MAYBE	REMOTE DEADLOCK SIMPLEFIX NETWORK  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
======================================================================

ActionableScore=1
ActionableScoreLower=0

## 1. ActionableScore

* Conservative score: 0
* Paranoid score: 1
* Final recommended bucket: **Ordinary Moderate / Low-like**::

## 2. Signal breakdown

Conservative signals:

* Reliable local DoS concern: +1. The bug can deadlock the mt76 driver control path during remain-on-channel handling.
* Requires CAP_NET_ADMIN or privileged WiFi management in typical deployments: -2. Direct triggering normally requires local wireless control-plane access through cfg80211/nl80211 or a privileged network management process.
* Device-specific WiFi driver path: -1. This is limited to mt76 hardware and the remain-on-channel feature, not a broad kernel core path.
* Availability impact realistic: +1. The affected wireless device or driver workflow may become stuck, but this is not shown as a reliable system-wide kernel crash.

Conservative total is effectively 0 after bounding as Low-like.

Paranoid signals:

* Local reduced-privilege trigger possible: +1. In some deployments, a local user may indirectly trigger remain-on-channel through delegated WiFi management, a service account, P2P workflow, or reduced network-administration capability.
* Reliable device-level DoS concern: +1. Recursive mutex acquisition can produce a deterministic deadlock in the affected path.
* Device-specific and configuration-dependent exposure: -1. The issue requires mt76 hardware and use of the remain-on-channel path.

Paranoid total: 1.

No memory corruption, UAF, OOB write, page-cache corruption, info leak, or privilege escalation primitive is supported by the patch.

## 3. Reachability analysis

The bug is triggered through local WiFi control-plane operations that invoke remain-on-channel handling. In normal deployments, this is mediated by privileged components such as wpa_supplicant, NetworkManager, hostapd, or processes with CAP_NET_ADMIN. Namespace or container delegation could lower practical privilege requirements if an untrusted actor is allowed to manage the wireless interface, but this is deployment-specific.

The path is not remotely network-triggerable by ordinary WiFi packets. It requires the affected mt76 driver and hardware, plus a workflow that enters remain-on-channel or ROC completion. Realistic exploitation is a local or delegated-control denial of service against the wireless device or driver control path, not host compromise.

## 4. Severity interpretation

This behaves like an ordinary Moderate or Low-like driver DoS issue. The theoretical impact is a deadlock due to incorrect mutex usage, not memory lifetime corruption. There is no evidence of attacker-controlled overwrite, stale pointer reuse, UAF reclaim, information disclosure, or LPE. The practical impact is loss of progress in mt76 WiFi operations and possible device-level availability degradation.

## 5. One-sentence report phrase

A local mt76 remain-on-channel operation can deadlock the WiFi driver because mt76_set_channel() is called while dev mutex is already held, causing a device-level denial of service without evidence of memory corruption or privilege escalation.

## 6. Manual review recommendation

NO MANUAL CHECK NEEDED

This is a locking bug with DoS-only impact, device-specific exposure, and no supported memory corruption or security-boundary bypass primitive.

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

Patch: wifi: mt76: fix deadlock in remain-on-channel [ Upstream
Commit: 5fc8c5d45e44575dda9fcabdc2aac4ad97baf0cd
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=5fc8c5d45e44575dda9fcabdc2aac4ad97baf0cd

Changed files:
  drivers/net/wireless/mediatek/mt76/channel.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=5fc8c5d45e44575dda9fcabdc2aac4ad97baf0cd

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

The original Linux kernel CVE announcement for CVE-2026-53100 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53100

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:N/I:N/A:H
  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: 0
  Paranoid ActionableScore: 1

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).