[CVE-2026-68439][LOW] wifi: mt76: mt7925: fix possible NULL-pointer deref in mt7925_mcu_bss_he_tlv() [ Upstream

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

CVE: CVE-2026-68439
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: wifi: mt76: mt7925: fix possible NULL-pointer deref in mt7925_mcu_bss_he_tlv() [ Upstream
Commit: 42288cca984fb72ad3ebe43d4e7fdce9dcabfdb5
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=42288cca984fb72ad3ebe43d4e7fdce9dcabfdb5
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68439
Analysis date: Tue, 11 Aug 2026 21:02:02 -0400
ActionableScore: 1
ActionableScore lower bound: 0
Actionable bucket: Ordinary Moderate / Low-like
Manual review required: NO

Summary:
A possible NULL pointer dereference in the mt7925 Wi-Fi driver may crash the kernel when HE PHY capability lookup fails during BSS HE TLV construction, but exploitation appears local, hardware-specific, and DoS-only.

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ABOUT THIS REPORT
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The original Linux kernel CVE announcement for CVE-2026-68439 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68439

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-2026-68439	LOW	CHECK WITH IMPACT FROM ORIG NN MODERATE	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H';**CWE-476;CWE-703;CWE-754;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '4.7';DESCR 'A NULL pointer dereference in the mt7925 Wi-Fi driver can occur because mt7925_mcu_bss_he_tlv may dereference the HE PHY capability pointer returned by mt76_connac_get_he_phy_cap even when that pointer is NULL. A local trigger would require mt7925 hardware and a configuration path that reaches BSS HE TLV construction while no matching HE PHY capability is available, making reliable exploitation hardware and state dependent. For the CVSS the PR:L is used in the paranoid score because a local unprivileged user may be able to request Wi-Fi configuration changes through a privileged network management service on some systems, while direct driver control is usually administrative. The issue is not directly network reachable and does not appear to be triggered by normal remote packet processing. Impact is denial of service via kernel crash only, with no supported path to information disclosure or privilege escalation.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 1)	YES	REMOTE SIMPLEFIX NETWORK  DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3	YES	NO	checked

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ACTIONABLESCORE ANALYSIS
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ActionableScore=1
ActionableScoreLower=0

## 1. ActionableScore

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

## 2. Signal breakdown

Triggered signals:

* Reliable kernel crash / strong DoS: +1
  Possible NULL pointer dereference if `mt76_connac_get_he_phy_cap()` returns NULL and the path reaches `mt7925_mcu_bss_he_tlv()`.

Paranoid-only signal:

* Local unprivileged trigger: +1
  In some desktop or managed-network setups, a local user may indirectly request Wi-Fi configuration changes through NetworkManager or another privileged service.

Subtracting signals:

* Requires admin/root/CAP_NET_ADMIN in typical deployments: -2
  Direct control of Wi-Fi driver configuration is normally privileged.
* Rare hardware / difficult-to-reach condition: -1
  Requires Mediatek mt7925 hardware and a specific state where HE PHY capabilities are unavailable.
* Hard or unreliable trigger: -1
  The commit says the helper can theoretically return NULL, but no reliable trigger or reproducer is shown.

Not applied:

* No generic memory corruption bonus. This is a NULL dereference, not UAF, OOB write, double free, type confusion, or refcount corruption.
* No privilege escalation bonus. No reclaim, overwrite, callback control, or object confusion is visible.
* No confidentiality or integrity impact. The patch only prevents dereferencing a NULL pointer.
* No remote/network reachable bonus. The issue is in local driver configuration / MCU TLV construction, not normal remote packet processing.

Call-site confidence: medium. The changed function is visible, but broader callers and exact user-triggerable paths are not included.

## 3. Reachability analysis

The bug is reachable only on systems using the mt7925 Wi-Fi driver. A realistic trigger likely requires local configuration activity such as interface setup, association, reconfiguration, or BSS parameter update. Direct triggering usually requires administrative control over Wi-Fi settings, typically CAP_NET_ADMIN or a privileged network-management daemon.

Namespaces and containers do not obviously lower the requirement unless the environment delegates Wi-Fi control or network administration to an untrusted user. The path is not remotely reachable through ordinary Wi-Fi frames based on the provided patch. A malicious AP influence is not clearly supported by the diff.

## 4. Severity interpretation

This behaves like a low-end Moderate or Low-like kernel issue. The realistic impact is local denial of service through a kernel crash on a hardware-specific path. Theoretical memory corruption is not supported because the primitive is a NULL pointer dereference only.

The paranoid interpretation only raises reachability to local unprivileged in environments where a user can indirectly trigger Wi-Fi reconfiguration through a privileged service. Even then, the outcome remains DoS-only and hardware/state dependent.

## 5. One-sentence report phrase

A possible NULL pointer dereference in the mt7925 Wi-Fi driver may crash the kernel when HE PHY capability lookup fails during BSS HE TLV construction, but exploitation appears local, hardware-specific, and DoS-only.

## 6. Manual review recommendation

NO MANUAL CHECK NEEDED

This can be auto-closed or handled in deferred maintenance for most products because it is a hardware-specific NULL dereference with no evidence of memory corruption, privilege escalation, information disclosure, or remote reachability.

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

Patch: wifi: mt76: mt7925: fix possible NULL-pointer deref in mt7925_mcu_bss_he_tlv() [ Upstream
Commit: 42288cca984fb72ad3ebe43d4e7fdce9dcabfdb5
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=42288cca984fb72ad3ebe43d4e7fdce9dcabfdb5

Changed files:
  drivers/net/wireless/mediatek/mt76/mt7925/mcu.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=42288cca984fb72ad3ebe43d4e7fdce9dcabfdb5

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

The original Linux kernel CVE announcement for CVE-2026-68439 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68439

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:H/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS score: 4.7

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).