[CVE-2026-74326][LOW] wifi: mt76: mt7921: fix resource leak in probe error path [ Upstream

[CVE-2026-74326][LOW] wifi: mt76: mt7921: fix resource leak in probe error path [ Upstream

[AL-KERNEL]

CVE: CVE-2026-74326
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: wifi: mt76: mt7921: fix resource leak in probe error path [ Upstream
Commit: 79a307b2730e4b4e060cf3e19a6c21b87116ee78
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=79a307b2730e4b4e060cf3e19a6c21b87116ee78
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74326
Analysis date: Sun, 16 Aug 2026 02:54:06 -0400
ActionableScore: 0
ActionableScore lower bound: unknown
Actionable bucket: Ordinary Moderate / Low-like
Manual review required: NO

Summary:
No one-sentence report phrase was found.

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

The original Linux kernel CVE announcement for CVE-2026-74326 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74326

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.

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

CVE-2026-74326	LOW	CHECK WITH IMPACT FROM ORIG NN IMPORTANT	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H';*CWE-401;*CWE-772;CWE-404;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '4.1';DESCR 'The mt7921 PCI probe error path could return directly after pcim_iomap_region or devm_kmemdup failure while leaving an allocated mt76 device and PCI IRQ vectors behind. This is a resource leak in an initialization error path rather than a memory corruption primitive. For the CVSS the PR:H is used because reliable triggering normally requires administrative control over PCI driver probe bind unbind or module handling, plus conditions that make the early allocation or mapping step fail. The issue is not network reachable and cannot be triggered by WiFi traffic alone. Impact is denial of service only through possible resource exhaustion after repeated failed probe attempts. No confidentiality or integrity impact is indicated by the bug class or patch context.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 0)  SKIP CVE-2026-74326 UNKNOWN SKIP The Fixes patch not applied yet, so unlikely that actual: ee5bb35d2b83fadc6920aa2478326fb50ea653a9 YES  NO NO unknown 	MAYBE	REMOTE INIT NOMEMCHK SIMPLEFIX LEAK ERRORPATH NETWORK  LOWERED_FROM_HIGH_BASED_ON_GUESSCVSS  DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN5 DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3	-	-	checked

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

ActionableScore=0

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

2. Signal breakdown
* Availability impact realistic: +1 only in a very limited sense. Repeated failed probe attempts could leak mt76 device state and PCI IRQ vectors, but a single failure is not shown to cause immediate system-wide failure.
* Requires admin/root/CAP_* in typical deployments: -2. Reliable triggering normally requires control over PCI driver probing, bind/unbind, module handling, or fault-injection style failure conditions.
* Hard or unreliable special condition: -1. The leak occurs only if `pcim_iomap_region()` or `devm_kmemdup()` fails after earlier allocations in the probe path.
* No memory corruption signal. The patch fixes missed cleanup in an error path, not UAF, OOB access, double free, type confusion, or arbitrary write.
* No confidentiality or integrity signal. The leaked objects are not shown to expose data or modify protected state.
* No remote or firmware-mediated trigger. WiFi traffic does not reach this probe error path.

3. Reachability analysis
The realistic trigger is local and privileged. An attacker would need the ability to influence PCI device probing or repeatedly bind, unbind, reload, or otherwise force the mt7921 PCI probe path to fail at the specific allocation or mapping points. Namespaces do not normally reduce this to an unprivileged trigger because PCI driver management is host-admin controlled. The affected driver is hardware-specific and the vulnerable path is an initialization error path, not a normal packet-processing or wireless data path.

4. Severity interpretation
This behaves like a Low-like or ordinary Moderate resource leak, not an actionable Moderate or Important kernel vulnerability. The theoretical worst case is resource exhaustion after repeated privileged probe failures, but the patch does not support memory corruption, privilege escalation, information disclosure, or a network-triggerable attack. The issue should not be treated like a kernel memory lifetime bug despite involving leaked kernel resources.

5. One-sentence report phrase
A cleanup bug in the mt7921 PCI probe error path can leak an allocated mt76 device and PCI IRQ vectors when early mapping or allocation fails, but triggering is privileged and the practical impact is limited to possible local resource exhaustion.

6. Manual review recommendation
NO MANUAL CHECK NEEDED
This is a privileged probe-path resource leak with no supported memory corruption primitive, no network reachability, and no plausible LPE or data exposure path.

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

Patch: wifi: mt76: mt7921: fix resource leak in probe error path [ Upstream
Commit: 79a307b2730e4b4e060cf3e19a6c21b87116ee78
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=79a307b2730e4b4e060cf3e19a6c21b87116ee78

Changed files:
  drivers/net/wireless/mediatek/mt76/mt7921/pci.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=79a307b2730e4b4e060cf3e19a6c21b87116ee78

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

The original Linux kernel CVE announcement for CVE-2026-74326 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74326

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:L
  The Best / paranoid CVSS vector: AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS score: 4.1

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: unknown
  Paranoid ActionableScore: 0

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).