[CVE-2026-80939][LOW] wifi: rtw89: pci: add .shutdown callback to stop rfkill polling on reboot

[CVE-2026-80939][LOW] wifi: rtw89: pci: add .shutdown callback to stop rfkill polling on reboot

[AL-KERNEL]

CVE: CVE-2026-80939
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: wifi: rtw89: pci: add .shutdown callback to stop rfkill polling on reboot
Commit: c1f214dd1351244156deb57761b14190a233aef6
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=c1f214dd1351244156deb57761b14190a233aef6
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-80939
Analysis date: Fri, 11 Sep 2026 19:50:01 -0400
ActionableScore: 1
ActionableScore lower bound: unknown
Actionable bucket: Ordinary Moderate
Manual review required: NO

Summary:
No one-sentence report phrase was found.

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

The original Linux kernel CVE announcement for CVE-2026-80939 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-80939

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-2026-80939	LOW	https://www.kernelcve.org/list/?q=CVE-2026-80939 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:H/UI:N/S:U/C:N/I:N/A:H';*CWE-672;CWE-404;CWE-703;Other CVSS 'AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '4.4';DESCR 'The rtw89 PCI driver did not stop hardware rfkill polling on the reboot shutdown path. During warm reboot the PCIe link can be torn down while rfkill_poll is still able to issue MMIO reads through rtw89_pci_ops_read8. On affected arm64 platforms a read from a non responding device can be reported as a fatal asynchronous SError and cause a kernel panic. For the CVSS the PR:H value is typical because reliably reaching this path usually requires permission to reboot or shut down the system. The issue is not network reachable and is not triggered by WiFi traffic. Impact is denial of service or reboot failure only, with no evidence of memory corruption, information disclosure, or privilege escalation.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 1)	YES	REMOTE READ INIT NETWORK HARDWARE LINUS BOOT TEST  DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3	YES	NO	checked

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

ActionableScore=1
PrimitiveClass=CLASS_C
RealUAF=NO
HostAdminRequired=YES
NamespaceScopedPrivilege=NO
ImportantCandidate=NO
ManualReview=NO
AutoDowngradeAllowed=YES

1. ActionableScore

* Raw conservative score: -1
* Conservative score: 1
* Raw paranoid score: -1
* Paranoid score: 1
* Applied normalization: confirmed kernel crash issue with negative raw score normalized to 1.
* Final recommended bucket: **Ordinary Moderate**::

2. Signal breakdown

Positive signals:

* +1 Reliable kernel crash / strong DoS: the supplied trace shows arm64 asynchronous SError leading to kernel panic during warm reboot.
* +0 Real UAF: not awarded. The patch does not establish freed kernel memory reuse, stale heap object dereference, double release, or refcount corruption.
* +0 Controlled corruption: not awarded. The MMIO read targets a non responding PCIe device after link teardown, not attacker controlled kernel memory.
* +0 Confidentiality or integrity: not awarded. No disclosure, overwrite, privilege escalation, authorization bypass, or security boundary violation is shown.
* +0 Remote reachability: not awarded. WiFi traffic does not reach the vulnerable condition.

Negative signals:

* -2 Host admin required: reliably reaching the vulnerable path requires reboot or shutdown of the host, normally CAP_SYS_BOOT or equivalent administrative control.
* +0 Hardware penalty not additionally applied: although the issue is specific to rtw89 PCI on affected arm64 platforms, the host admin reboot requirement already captures the main practical restriction and avoids double counting.

Important non-awarded signals:

* Controlled reclaim not demonstrated.
* Arbitrary write not demonstrated.
* UAF not demonstrated.
* Repeated release or refcount mutation not demonstrated.
* Extra availability point not awarded because the same kernel panic is already counted once.
* Network reachability not established.
* ImportantCandidate not set because the demonstrated issue is admin-triggered reboot-path DoS only.

3. Reachability analysis

The trigger is the system reboot or shutdown path. During device_shutdown(), .remove is not called, and without an rtw89 PCI .shutdown callback the rfkill polling work can continue while the PCIe link is being torn down. A subsequent MMIO read to a non responding device may raise a fatal asynchronous SError on affected arm64 systems.

The complete trigger normally requires host administrator capability to reboot or shut down the system. There is no evidence that an ordinary local user, a namespace scoped capability, WiFi traffic, or a remote network peer can trigger the vulnerable path. No prior attacker controlled setup is shown beyond having affected rtw89 PCI hardware and hardware rfkill polling enabled by the driver. This is not a timing race that provides attacker controlled exploitation leverage. It is a shutdown ordering bug.

4. Primitive and severity interpretation

The exact primitive is an invalid MMIO access after PCIe teardown during the reboot shutdown path. This is not active structured kernel object UAF and not fixed stale heap storage UAF. It is best classified as CLASS_C because the demonstrated behavior is a fatal device access during teardown resulting in panic.

The demonstrated consequence is denial of service or reboot failure on affected arm64 platforms. The speculative consequence beyond crash is weak because no memory corruption, no post lifetime object use, no attacker selected target, no attacker controlled payload, no refcount mutation, and no boundary bypass are established.

ImportantCandidate=NO because there is no Important preserving primitive and no unresolved Class B lifetime or corruption leverage. AutoDowngradeAllowed=YES because the issue is constrained to host admin initiated reboot or shutdown and the only demonstrated impact is crash or reboot failure.

Likely operational severity is Low to ordinary Moderate.

5. One-sentence report phrase

The rtw89 PCI driver could continue rfkill polling during warm reboot after PCIe teardown, causing an MMIO read to a non responding device and an arm64 SError kernel panic, but the trigger normally requires host administrator reboot control and does not show memory corruption or privilege escalation.

6. Manual review recommendation

NO MANUAL CHECK NEEDED

Reason: this is a constrained host-admin-triggered reboot-path DoS with no UAF, no corruption primitive, no remote reachability, and no security-boundary bypass shown.

7. Call-site confidence

Call-site confidence: high

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

Patch: wifi: rtw89: pci: add .shutdown callback to stop rfkill polling on reboot
Commit: c1f214dd1351244156deb57761b14190a233aef6
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=c1f214dd1351244156deb57761b14190a233aef6

Commit description:

Since the hardware rfkill polling was introduced, arm64 platforms can
panic with an asynchronous SError during warm reboot:

  SError Interrupt on CPU8, code 0x00000000be000011 -- SError
  Workqueue: events_power_efficient rfkill_poll [rfkill]
    rtw89_pci_ops_read8+0x94/0x160 [rtw89_pci]
    rtw89_core_rfkill_poll+0x50/0x1e0 [rtw89_core]
    rtw89_ops_rfkill_poll+0x40/0x68 [rtw89_core]
    ieee80211_rfkill_poll+0x3c/0x70 [mac80211]
    cfg80211_rfkill_poll+0x40/0x2a0 [cfg80211]
    rfkill_poll+0x30/0x88 [rfkill]
  Kernel panic - not syncing: Asynchronous SError Interrupt

On the reboot path the kernel only runs device_shutdown(), which calls
each driver's .shutdown callback; .remove is not invoked.  The rtw89 PCI
driver had no .shutdown callback, so nothing stopped the rfkill polling
work while the platform was tearing the PCIe link down.  Once the link
is gone, the next MMIO read from the poll handler targets a
non-responding device and is reported as a fatal asynchronous SError on
arm64.

Add rtw89_pci_shutdown(), wired to all rtw89 PCI device drivers, which
sets a new RTW89_FLAG_SHUTDOWN flag (mirroring the USB
RTW89_FLAG_UNPLUGGED pattern).  When the flag is set,
rtw89_ops_rfkill_poll() returns early, so no MMIO read is issued to the
chip after shutdown begins and the SError no longer occurs.

This does not call the full .remove path from .shutdown, to keep the
shutdown handler minimal and avoid running the non-idempotent teardown
twice.

Fixes: 0b38e62 ("wifi: rtw89: add support for hardware rfkill")
Cc: stable@vger.kernel.org
Suggested-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Yuhang.chen <yhchen312@gmail.com>
Acked-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://patch.msgid.link/20260729014142.2746777-1-yhchen312@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Changed files:
  drivers/net/wireless/realtek/rtw89/core.h
  drivers/net/wireless/realtek/rtw89/mac80211.c
  drivers/net/wireless/realtek/rtw89/pci.c
  drivers/net/wireless/realtek/rtw89/pci.h
  drivers/net/wireless/realtek/rtw89/rtw8851be.c
  drivers/net/wireless/realtek/rtw89/rtw8852ae.c
  drivers/net/wireless/realtek/rtw89/rtw8852be.c
  drivers/net/wireless/realtek/rtw89/rtw8852bte.c
  drivers/net/wireless/realtek/rtw89/rtw8852ce.c
  drivers/net/wireless/realtek/rtw89/rtw8922ae.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=c1f214dd1351244156deb57761b14190a233aef6

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

The original Linux kernel CVE announcement for CVE-2026-80939 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-80939

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:L
  The Best / paranoid CVSS vector: AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS score: 4.4

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: 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).