[CVE-2026-53105][MODERATE REGULAR] wifi: mt76: mt7925: prevent NULL vif dereference in mt7925_mac_write_txwi [ Upstream

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

CVE: CVE-2026-53105
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: wifi: mt76: mt7925: prevent NULL vif dereference in mt7925_mac_write_txwi [ Upstream
Commit: 6c52fbdc6f656ac2e8ed1e3d0f42ed21ef285e15
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=6c52fbdc6f656ac2e8ed1e3d0f42ed21ef285e15
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53105
Analysis date: Thu, 25 Jun 2026 13:59:29 -0400
ActionableScore: 3
ActionableScore lower bound: 1
Actionable bucket: Borderline manual review recommended / Ordinary Moderate likely
Manual review required: YES

Summary:
A NULL pointer dereference in the mt7925 WiFi TX descriptor path may crash the kernel when `mt7925_mac_write_txwi()` is called with an uninitialized `vif`, with realistic impact limited to DoS and no demonstrated memory corruption or privilege escalation primitive.

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

The original Linux kernel CVE announcement for CVE-2026-53105 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53105

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-2026-53105	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-476;CWE-703;CWE-754;Other CVSS 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '5.3';DESCR 'A NULL pointer dereference can occur in the mt7925 WiFi transmit descriptor path because mt7925_mac_write_txwi calls ieee80211_vif_is_mld(vif) before confirming that vif is initialized. If this path is reached with a NULL vif, the kernel can crash and the practical impact is denial of service. For the CVSS the PR:N is used for the paranoid adjacent wireless interpretation because a nearby attacker may not need a local account if the affected TX path can be reached through WiFi interaction. The base interpretation remains local PR:L because reliable triggering may require a local user or process that can drive the interface into the relevant transmit state. The issue is not evidence of UAF, OOB access, or arbitrary write, so confidentiality and integrity are not raised beyond none.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline manual review recommended / Ordinary Moderate likely (with actual score 2) 	MAYBE	REMOTE DANGER SIMPLEFIX NETWORK  DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH	-	-	checked

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ACTIONABLESCORE ANALYSIS
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ActionableScore=3
ActionableScoreLower=1

## 1. ActionableScore

* Conservative score: 1
* Paranoid score: 3
* Final recommended bucket: **Borderline manual review recommended / Ordinary Moderate likely**::

## 2. Signal breakdown

Conservative signals:

* Reliable kernel crash / strong DoS: +1
  The patch prevents a NULL `vif` dereference in `mt7925_mac_write_txwi()`, which can cause a kernel panic if the path is reached with an uninitialized `vif`.

* Hard or unreliable trigger / special driver state required: -1
  The patch does not show a direct packet parser or simple userspace API trigger. The vulnerable state depends on the mt7925 transmit path reaching this function with `vif == NULL`.

* Local unprivileged trigger plausible: +1
  A local unprivileged user may be able to generate transmit activity once the WiFi interface is configured, but reliable control over the NULL `vif` condition is not demonstrated.

Paranoid additional signals:

* Availability impact realistic: +1
  If triggered, the impact is host-wide kernel crash rather than a contained device error.

* Broad/common subsystem exposure: +1
  WiFi client drivers are commonly deployed, although this specific issue is limited to MediaTek mt7925 hardware and the mt76 driver path.

Not counted:

* No generic memory corruption: 0
  This is a NULL pointer dereference, not UAF, OOB write, double-free, type confusion, or arbitrary write.

* No privilege escalation plausible: 0
  The patch shows no reclaim primitive, controlled overwrite, object confusion, or data corruption path.

* No remote/network-triggerable score: 0
  This is in the TX descriptor construction path, not a clear remote RX parsing path. Adjacent wireless influence is possible enough for review, but not strong enough to count as remote reachable.

## 3. Reachability analysis

The most realistic trigger is local activity that drives the mt7925 WiFi transmit path while the driver has no initialized `vif` for the packet or descriptor context. A nearby wireless attacker might influence association or link state timing, but the patch does not demonstrate that an unauthenticated adjacent attacker can reliably force the NULL `vif` state.

Namespaces and containers do not materially improve reachability unless the container is delegated control of the WiFi interface. In normal deployments, WiFi device management is usually controlled by host network services or privileged users, but ordinary local users may still generate network traffic through an already configured interface.

The affected path is hardware and driver specific. It applies only to systems using the mt7925 mt76 WiFi driver.

## 4. Severity interpretation

This behaves like an ordinary Moderate kernel DoS with a manual-review reason due to WiFi adjacency uncertainty. The realistic impact is kernel crash only.

The theoretical risk does not rise to Important because there is no evidence of memory corruption beyond NULL dereference, no UAF lifetime issue, no controlled overwrite, no information leak, and no practical privilege escalation primitive. The paranoid score is only raised to ensure the adjacent-wireless triggerability question is not auto-closed without review.

## 5. One-sentence report phrase

A NULL pointer dereference in the mt7925 WiFi TX descriptor path may crash the kernel when `mt7925_mac_write_txwi()` is called with an uninitialized `vif`, with realistic impact limited to DoS and no demonstrated memory corruption or privilege escalation primitive.

## 6. Manual review recommendation

MANUAL CHECK RECOMMENDED

Manual review should verify whether a nearby wireless peer or an unprivileged local user can reliably drive the TX path into the `vif == NULL` state. If not, this can likely be treated as ordinary Moderate or Low-like device-specific DoS.

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

Patch: wifi: mt76: mt7925: prevent NULL vif dereference in mt7925_mac_write_txwi [ Upstream
Commit: 6c52fbdc6f656ac2e8ed1e3d0f42ed21ef285e15
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=6c52fbdc6f656ac2e8ed1e3d0f42ed21ef285e15

Changed files:
  drivers/net/wireless/mediatek/mt76/mt7925/mac.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=6c52fbdc6f656ac2e8ed1e3d0f42ed21ef285e15

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

The original Linux kernel CVE announcement for CVE-2026-53105 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53105

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:H/PR:L/UI:N/S:U/C:N/I:N/A:H
  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).