[CVE-2026-89523][MODERATE 7.0] wifi: mt76: mt7925: cancel pending mlo_pm_work

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

CVE: CVE-2026-89523
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: YES
Patch: wifi: mt76: mt7925: cancel pending mlo_pm_work
Commit: 5be6d02837d418bc6c805b5cab1b338de6de9ca7
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=5be6d02837d418bc6c805b5cab1b338de6de9ca7
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-89523
Analysis date: Fri, 11 Sep 2026 19:45:19 -0400
ActionableScore: 5
ActionableScore lower bound: 4
Actionable bucket: Actionable Moderate / Strong Important candidate requiring manual review
Manual review required: YES

Summary:
No one-sentence report phrase was found.

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

The original Linux kernel CVE announcement for CVE-2026-89523 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-89523

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 7.0
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-2026-89523	MODERATE	https://www.kernelcve.org/list/?q=CVE-2026-89523 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:H/I:H/A:H';*CWE-416;CWE-362;CWE-667;Other CVSS 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '7';DESCR 'A race in the mt7925 WiFi driver can leave mlo_pm_work pending while the device is reset, suspended, or unregistered. If the delayed work runs after the device state becomes invalid, it may access vif or bss data that was already freed or try to send MCU commands while firmware is unavailable. For the CVSS the PR:L value is used because reliable triggering typically requires a local user or local service able to initiate WiFi power management, suspend, reset, or device lifecycle transitions, but not necessarily full root privileges in common desktop deployments. The issue is not directly network reachable based on the patch alone. Impact is at least local denial of service via kernel crash. In the paranoid case it may allow confidentiality or integrity impact because the bug class is a race with a possible use-after-free on driver and wireless interface state.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Actionable Moderate / Strong Important candidate requiring manual review (with actual score 5)	YES	REMOTE SIMPLEFIX NETWORK HARDWARE KPANIC 	YES	NO	checked

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

ActionableScore=5
ActionableScoreLower=4
PrimitiveClass=CLASS_B
RealUAF=YES
HostAdminRequired=UNKNOWN
NamespaceScopedPrivilege=NO
ImportantCandidate=YES
ManualReview=REQUIRED
AutoDowngradeAllowed=NO

1. ActionableScore

* Raw conservative score: 3
* Conservative score: 4
* Raw paranoid score: 4
* Paranoid score: 5
* Final recommended bucket: **Actionable Moderate / Strong Important candidate requiring manual review**::

Conservative floor applied: 3 -> 4 because a real post-lifetime async work UAF is directly implied and host-admin-equivalent reachability is not positively established.

Paranoid floor applied: 4 -> 5 because the stale work is not just a fixed stale buffer or shallow cleanup dereference. It may consume active vif/bss state and interact with firmware after reset, suspend, or unregister.

2. Signal breakdown

Positive conservative signals:

* +2 Real UAF / active lifetime violation. The pending delayed work may run after device state, vif, or bss data has become invalid or freed.
* +1 Reliable kernel crash / strong DoS. Accessing freed wireless interface state or sending MCU commands after firmware teardown can realistically crash or wedge the driver/kernel path.

Positive paranoid signals:

* +2 Real UAF / active lifetime violation. Same as conservative.
* +1 Reliable kernel crash / strong DoS. Same as conservative.
* +1 Structured stale-object exploitation leverage. The stale operation is delayed work that may process active vif/bss driver state and issue MCU commands, not merely a destructor-only stale pointer read.

Non-awarded or limited signals:

* Controlled reclaim is not demonstrated.
* Arbitrary kernel read/write is not demonstrated.
* Callback or function pointer control is not demonstrated.
* Concrete repeated release/refcount mutation is not established.
* Extra Availability is not awarded because the same crash/hang consequence is already counted once.
* C/I impact is not awarded in the conservative score merely because UAF could theoretically corrupt reclaimed memory.
* Remote network reachability is not established from the patch alone.
* No race penalty is applied merely because this is a race. The evidence does not prove a uniquely hard or one-shot timing condition.
* No hardware rarity penalty is applied. mt7925 is hardware-specific, but the patch does not establish rare or physical-only attacker requirements.

Repeated release/refcount check:

* First release can end lifetime: not established as a concrete put/release sequence.
* Exact same reference survives to a second lifetime mutation: not established.
* Second operation mutates lifetime/refcount: not established.
* Concrete repeated release/refcount +1 awarded: no.
* Paranoid repeated-refcount leverage +1 awarded: no.
* FLOOR 5 applied: yes, but due to active structured post-lifetime work, not due to repeated refcount mutation.

3. Reachability analysis

The complete trigger is partially unresolved. The relevant paths are reset recovery, PCIe unregister, PCI suspend, mac80211 suspend, and USB suspend. Some paths, such as PCIe unbind or unregister, usually require host-administrative control. Other paths, such as suspend/resume or WiFi power-management transitions, may be reachable through local desktop policy, system services, or device/firmware events without full host root, but this is not fully established by the supplied patch.

HostAdminRequired is therefore UNKNOWN, not YES. The evidence does not prove host-admin-equivalent privilege is mandatory for every practical trigger, but it also does not fully prove ordinary unprivileged reachability for the complete vulnerable sequence.

NamespaceScopedPrivilege is NO because this is a physical WiFi driver lifecycle/power-management path, not a namespace-scoped network object path.

Prior host setup exists in the sense that affected mt7925 hardware and the driver must be present and active. This is not treated as a rare-subsystem penalty. No direct packet-triggered remote path is established. A nearby WiFi peer might influence link state indirectly, but the patch does not establish a complete adjacent-network trigger.

Race repeatability is plausible because reset/suspend/lifecycle transitions can occur multiple times, but exact attacker control over the vulnerable timing window is not proven.

4. Primitive and severity interpretation

The exact primitive is an async delayed-work lifetime bug. mlo_pm_work can remain queued while mt7925 device state is reset, suspended, or unregistered. If it executes afterward, it may access freed vif/bss state or operate on firmware/HIF state that is no longer valid.

This is an active structured-object UAF candidate, not fixed stale storage. The stale work can consume wireless interface state and issue MCU commands. It is also not purely cleanup/destructor-only, because the vulnerable operation is a delayed worker running after lifecycle invalidation.

PrimitiveClass is CLASS_B. A real lifetime violation is established, but there is no demonstrated controlled reclaim, arbitrary write, callback hijack, or concrete privilege-escalation chain.

The demonstrated consequence is local denial of service through kernel crash, driver crash, or invalid firmware interaction. The speculative consequence is stronger memory-corruption impact if freed vif/bss memory is reused in a way that the delayed worker later interprets as valid state. That stronger path is technically plausible enough for manual review but not established enough for CLASS_A.

ImportantCandidate is YES because this is an active structured UAF in a driver workqueue path with unresolved post-lifetime processing. AutoDowngradeAllowed is NO because automatically treating it as ordinary crash-only cleanup would discard meaningful unresolved lifetime-corruption leverage.

Likely operational severity: Actionable Moderate at minimum, with manual review needed to decide whether it reaches Important in a specific product or deployment.

5. One-sentence report phrase

A pending mt7925 mlo_pm_work item can run after reset, suspend, or unregister and access freed vif/bss state or invalid firmware state, causing at least local DoS and requiring manual review for possible UAF exploitation impact.

6. Manual review recommendation

MANUAL CHECK REQUIRED

Reason: real async workqueue UAF is directly implied, stale use involves active structured WiFi interface state, and the complete exploitation leverage is unresolved.

7. Call-site confidence

Call-site confidence: medium

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

Patch: wifi: mt76: mt7925: cancel pending mlo_pm_work
Commit: 5be6d02837d418bc6c805b5cab1b338de6de9ca7
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=5be6d02837d418bc6c805b5cab1b338de6de9ca7

Commit description:

If the device is reset, suspended or unregistered within that window,
the pending work can still run and access vif/bss data that may already
be freed, or send MCU commands while the firmware is not available.

Add cancel_delayed_work_sync(&dev->mlo_pm_work) in all relevant teardown
and suspend paths:

 - mt7925_mac_reset_work()        (chip reset recovery)
 - mt7925e_unregister_device()    (PCIe unbind)
 - mt7925_pci_suspend()           (PCIe bus suspend)
 - mt7925_suspend()               (mac80211 suspend)
 - mt7925u_suspend()              (USB bus / runtime suspend)

This ensures the work is stopped before the device state becomes
invalid.

Assisted-by: kimi-cli:kimi-k2.7 code
Assisted-by: atomcode:glm-5.2 #Reported-by

Fixes: 276a568 ("wifi: mt76: mt7925: update the power-saving flow")
Cc: stable@vger.kernel.org
Signed-off-by: Wentao Guan <guanwentao@uniontech.com>
Link: https://patch.msgid.link/20260630090218.3202029-1-guanwentao@uniontech.com
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Changed files:
  drivers/net/wireless/mediatek/mt76/mt7925/mac.c
  drivers/net/wireless/mediatek/mt76/mt7925/main.c
  drivers/net/wireless/mediatek/mt76/mt7925/pci.c
  drivers/net/wireless/mediatek/mt76/mt7925/usb.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=5be6d02837d418bc6c805b5cab1b338de6de9ca7

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

The original Linux kernel CVE announcement for CVE-2026-89523 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-89523

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:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
  The Best / paranoid CVSS score: 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: 4
  Paranoid ActionableScore: 5

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: YES
Published priority for this report (same as in Subject): MODERATE 7.0

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).