[CVE-2026-68309][LOW] wifi: mt76: connac: fix possible NULL-pointer deref in mt76_connac_mcu_uni_bss_he_tlv() [ Upstream

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

CVE: CVE-2026-68309
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: wifi: mt76: connac: fix possible NULL-pointer deref in mt76_connac_mcu_uni_bss_he_tlv() [ Upstream
Commit: b09508dd7bc4a8948ea00603041a918c09788502
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=b09508dd7bc4a8948ea00603041a918c09788502
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68309
Analysis date: Mon, 10 Aug 2026 17:04:26 -0400
ActionableScore: 2
ActionableScore lower bound: 0
Actionable bucket: Ordinary Moderate / Low-like
Manual review required: NO

Summary:
A possible NULL-pointer dereference in the mt76 connac WiFi HE BSS MCU setup path can crash the kernel when HE capability lookup returns NULL, but exploitation appears limited to local or delegated WiFi configuration on affected Mediatek hardware.

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ABOUT THIS REPORT
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The original Linux kernel CVE announcement for CVE-2026-68309 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68309

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-2026-68309	LOW	CHECK WITH IMPACT FROM ORIG NN MODERATE	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-476;CWE-252;CWE-754;Other CVSS 'AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '5.5';DESCR 'A NULL-pointer dereference can occur in the mt76 connac WiFi driver because mt76_connac_get_he_phy_cap() can theoretically return NULL and mt76_connac_mcu_uni_bss_he_tlv() dereferenced the returned cap pointer while building HE BSS MCU data. Triggering requires a Mediatek mt76 connac device and a configuration path that builds HE BSS TLVs, such as local wireless interface setup or association management on an affected system. For the CVSS the PR:L is used in the paranoid score because some deployments delegate WiFi configuration to local users or service accounts, although direct kernel configuration normally requires CAP_NET_ADMIN. The issue is not directly network reachable from arbitrary packet traffic. Impact is denial of service via kernel crash only.';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	NO	NO	checked

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ACTIONABLESCORE ANALYSIS
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ActionableScore=2
ActionableScoreLower=0

## 1. ActionableScore

* Conservative score: 0
* Paranoid score: 2
* Final recommended bucket: **Ordinary Moderate / Low-like**::

## 2. Signal breakdown

Conservative signals:

* Reliable kernel crash / strong DoS: +1. The patch prevents a possible NULL-pointer dereference in `mt76_connac_mcu_uni_bss_he_tlv()`.
* Requires admin/root/CAP_NET_ADMIN in typical deployments: -2. Normal wireless interface configuration and driver control paths usually require administrative privileges or a privileged network-management service.
* Hardware/device specific path: -1. The bug is limited to Mediatek mt76 connac WiFi devices and the HE BSS MCU TLV setup path.

Paranoid signals:

* Local unprivileged or delegated local trigger: +1. Some desktop or appliance deployments delegate WiFi association and configuration to local users through NetworkManager, wpa_supplicant, or a service account.
* Reliable kernel crash / strong DoS: +1. If the NULL return is reachable, dereferencing `cap` can crash the kernel.
* No memory corruption bonus. This is a NULL-pointer dereference only, with no UAF, OOB write, object reuse, callback corruption, or attacker-controlled overwrite shown.
* No LPE bonus. There is no plausible privilege-escalation primitive in the patch context.

## 3. Reachability analysis

The affected path is in the mt76 connac WiFi driver while building HE BSS MCU data. A realistic trigger requires an affected Mediatek mt76 connac device and a configuration or association path where `mt76_connac_get_he_phy_cap()` can return NULL.

In typical deployments, direct control of the relevant wireless configuration path requires CAP_NET_ADMIN or a privileged network-management daemon, so the conservative interpretation is privileged local reachability. In more permissive desktop or appliance setups, a local user may indirectly trigger WiFi configuration changes through delegated services, which supports the paranoid PR:L-style interpretation.

The issue is not directly network reachable from arbitrary WiFi packets based on the provided patch. A remote AP or environment may influence association context, but the patch does not show a direct remote packet parsing vulnerability.

Call-site confidence: medium. The changed function and immediate dereference are visible, but broader call paths are not included in the input.

## 4. Severity interpretation

This behaves like an ordinary Moderate or Low-like kernel DoS issue, not an Important-class vulnerability. The demonstrated primitive is a NULL-pointer dereference, not generic memory corruption.

Theoretical impact is kernel crash or driver-triggered system DoS if the NULL path is reachable. Realistic exploitation is limited by hardware dependency, local configuration requirements, and lack of evidence for UAF, overwrite, information disclosure, or privilege escalation.

## 5. One-sentence report phrase

A possible NULL-pointer dereference in the mt76 connac WiFi HE BSS MCU setup path can crash the kernel when HE capability lookup returns NULL, but exploitation appears limited to local or delegated WiFi configuration on affected Mediatek hardware.

## 6. Manual review recommendation

NO MANUAL CHECK NEEDED

Reason: the patch shows a simple NULL check for a possible NULL return, with DoS-only impact and no concrete memory corruption or privilege-escalation primitive.

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

Patch: wifi: mt76: connac: fix possible NULL-pointer deref in mt76_connac_mcu_uni_bss_he_tlv() [ Upstream
Commit: b09508dd7bc4a8948ea00603041a918c09788502
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=b09508dd7bc4a8948ea00603041a918c09788502

Changed files:
  drivers/net/wireless/mediatek/mt76/mt76_connac_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=b09508dd7bc4a8948ea00603041a918c09788502

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

The original Linux kernel CVE announcement for CVE-2026-68309 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68309

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: 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).