[CVE-2026-53317][MODERATE REGULAR] wifi: mt76: mt7921: Place upper limit on station AID [ Upstream

[CVE-2026-53317][MODERATE REGULAR] wifi: mt76: mt7921: Place upper limit on station AID [ Upstream

[AL-KERNEL]

CVE: CVE-2026-53317
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: wifi: mt76: mt7921: Place upper limit on station AID [ Upstream
Commit: 6dbe70f9ef14d8ac1c24bf19fd9510978a3ab952
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=6dbe70f9ef14d8ac1c24bf19fd9510978a3ab952
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53317
Analysis date: Fri, 26 Jun 2026 16:20:21 -0400
ActionableScore: 3
ActionableScore lower bound: 1
Actionable bucket: Borderline, manual review recommended
Manual review required: YES

Summary:
A missing upper bound check for mt7921 station AID values can pass unsupported AIDs over 20 to firmware in AP mode, causing a firmware crash and adjacent-network DoS in affected non-default AP configurations.

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

The original Linux kernel CVE announcement for CVE-2026-53317 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53317

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.

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

CVE-2026-53317	MODERATE	CHECK	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H';*CWE-20;CWE-754;**CWE-400;Other CVSS 'AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '5.3';DESCR 'A missing upper bound check for station AID in the mt7921 AP path can pass AID values over 20 to the device firmware and crash the firmware. The issue was observed with an AP interface and a modified hostapd configuration that assigned high AID values, while stock hostapd is described as normally preventing this condition through station limits. For the CVSS the PR:N reflects the paranoid adjacent attacker scenario where no local account is needed, but triggering depends on WiFi association behavior and an AP setup that can assign AID values over 20. The issue is adjacent network reachable rather than Internet reachable because the attacker must be in WiFi radio range of the affected AP. Impact is denial of service of the wireless firmware or AP function. No kernel memory corruption, information disclosure, or privilege escalation primitive is supported by the patch context.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline, manual review recommended (with actual score 2)	YES	REMOTE DANGER SIMPLEFIX NETWORK KERNEL_PANIC_PLUS_UAF HARDWARE TEST  DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH	NO	NO	checked

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

ActionableScore=3
ActionableScoreLower=1

## 1. ActionableScore

* Conservative score: 1
* Paranoid score: 3
* Final recommended bucket: **Borderline, manual review recommended**::

## 2. Signal breakdown

Paranoid score signals:

* Firmware-mediated external influence: +1. A WiFi station association can indirectly reach the affected firmware path if the AP setup assigns station AID values over 20.
* Reliable firmware crash / strong DoS: +1. The commit explicitly states that AID values over 20 cause a firmware crash.
* Availability impact realistic: +1. On affected AP-mode deployments, the crash can disrupt wireless AP functionality.

Conservative score signals:

* Reliable firmware crash / strong DoS: +1. The failure mode is a firmware crash.
* Requires admin/root/CAP_NET_ADMIN in typical deployments: -2. The realistic observed trigger requires AP mode and a modified hostapd or equivalent AP control.
* Availability impact realistic: +1. The impact is loss of wireless firmware/AP function.
* Legacy / non-default execution mode or configuration dependency: +0 or -1. I would not strongly penalize this because vendor OpenWRT feeds and AP mode are plausible, but stock hostapd normally prevents the condition.

No memory corruption, UAF, OOB write, refcount bug, type confusion, kernel info leak, or privilege escalation primitive is shown by the patch.

## 3. Reachability analysis

The conservative trigger requires a local administrator or network-management process that can run AP mode and configure hostapd behavior. Stock hostapd normally starts station AIDs at 1 and limits associated stations, so the bad AID range is not expected in default configurations.

The paranoid trigger is adjacent-network: a WiFi client in radio range may be able to trigger the crash by associating to an affected AP if that AP uses modified or vendor hostapd behavior that assigns AID values over 20. This is not Internet-reachable and not a generic remote network packet path.

Namespaces and containers generally do not lower the privilege requirement unless the container or service is delegated control over the wireless AP interface and hostapd configuration.

## 4. Severity interpretation

This behaves like a firmware-level DoS rather than a kernel memory corruption vulnerability. The patch is an input-validation fix that rejects unsupported station AID values before firmware programming.

The realistic severity is ordinary Moderate or Low-like because the known trigger depends on AP mode and non-stock hostapd behavior. The paranoid severity reaches borderline manual-review territory because an adjacent WiFi attacker may be able to cause AP disruption in affected deployments without a local account.

It does not look like an Important-class kernel vulnerability because there is no evidence of kernel memory corruption, privilege escalation, confidentiality impact, or integrity impact.

## 5. One-sentence report phrase

A missing upper bound check for mt7921 station AID values can pass unsupported AIDs over 20 to firmware in AP mode, causing a firmware crash and adjacent-network DoS in affected non-default AP configurations.

## 6. Manual review recommendation

MANUAL CHECK RECOMMENDED

Manual review is recommended because the conservative case is low-risk local/AP configuration misuse, but the paranoid adjacent WiFi DoS scenario is plausible for affected AP deployments using modified or vendor hostapd behavior.

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

Patch: wifi: mt76: mt7921: Place upper limit on station AID [ Upstream
Commit: 6dbe70f9ef14d8ac1c24bf19fd9510978a3ab952
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=6dbe70f9ef14d8ac1c24bf19fd9510978a3ab952

Changed files:
  drivers/net/wireless/mediatek/mt76/mt7921/main.c
  drivers/net/wireless/mediatek/mt76/mt7921/mt7921.h

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=6dbe70f9ef14d8ac1c24bf19fd9510978a3ab952

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

The original Linux kernel CVE announcement for CVE-2026-53317 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53317

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:L
  The Best / paranoid CVSS vector: AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS score: 5.3

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: 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).