[CVE-2026-74407][MODERATE 7.0] wifi: ath11k: cancel SSR work items during PCI shutdown [ Upstream

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

CVE: CVE-2026-74407
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: wifi: ath11k: cancel SSR work items during PCI shutdown [ Upstream
Commit: 53dd29e8aeb2a1b5f079178551836b85fc6b53df
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=53dd29e8aeb2a1b5f079178551836b85fc6b53df
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74407
Analysis date: Sat, 15 Aug 2026 19:20:24 -0400
ActionableScore: 5
ActionableScore lower bound: 3
Actionable bucket: Actionable Moderate at minimum
Manual review required: YES

Summary:
A race between ath11k PCI shutdown and firmware SSR recovery can cause overlapping MHI teardown of DMA-backed contexts, leading to a NULL pointer dereference and kernel crash, with practical reachability mainly limited to PCI/MHI ath11k devices during reboot or device shutdown.

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

The original Linux kernel CVE announcement for CVE-2026-74407 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74407

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-2026-74407	MODERATE	CHECK WITH IMPACT FROM ORIG NN LOW	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:H';CWE-362;**CWE-476;CWE-415;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '5.8';DESCR 'A race in ath11k PCI shutdown can overlap with firmware crash recovery SSR work. The RDDM callback can queue reset_work, while the shutdown path also calls ath11k_pci_power_down, so MHI teardown and DMA backed context freeing can run in an unsafe overlapping sequence. The observed failure is a NULL pointer dereference in the MHI teardown path during reboot, causing a kernel crash. For the CVSS the PR:L is used in the paranoid score for environments where a lower privileged local process or service can trigger firmware recovery or device reset behavior while shutdown is in progress. The base case is closer to PR:H because reboot and PCI teardown are normally administrator controlled. The issue is not directly network reachable from the patch context. Impact is at least denial of service. In the worst defensible case, limited confidentiality or integrity impact is kept for manual review because the race touches DMA and MHI lifetime handling, but no stable arbitrary write primitive is shown.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Actionable Moderate at minimum (with actual score 4)	YES	REMOTE LOCK NULLPTR INIT RACE NETWORK DMAorINTERRUPT KERNEL_PANIC_PLUS_UAF HARDWARE DEBUGFS LINUS BOOT MEMORY  DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN5	NO	NO	checked

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ACTIONABLESCORE ANALYSIS
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ActionableScore=5
ActionableScoreLower=3

## 1. ActionableScore

* Conservative score: **3**
* Paranoid score: **5**
* Final recommended bucket: **Actionable Moderate at minimum**::

## 2. Signal breakdown

Conservative signals:

* **Weak/indirect corruption candidate: +1**. The bug is an async race where MHI teardown and DMA-backed context freeing can be reached from two paths, but the demonstrated symptom is a NULL pointer dereference rather than controlled UAF reuse or arbitrary write.
* **Real lifetime corruption: +1**. The fix prevents SSR work from overlapping shutdown and prevents MHI/DMA teardown from running more than once.
* **Reliable kernel crash / strong DoS: +1**. The commit gives a concrete crash trace during reboot.
* **Privileged kernel/device-management lifetime path: +1**. The affected code is PCI/MHI device teardown with DMA-backed resources.
* **Requires admin/root in typical deployments: -2**. Reboot and PCI shutdown are normally administrator-controlled.
* **Hard or unreliable race / special timing required: -1**. The crash requires overlap between reboot/shutdown and firmware SSR recovery.
* **Availability impact realistic: +1**. The failure can crash the kernel and disrupt reboot or shutdown completion.

Paranoid additions / changes:

* **Firmware-mediated external influence: +1**. SSR is driven by firmware crash recovery, and firmware crash conditions may sometimes be influenced by device or WLAN environment, but this is not enough to classify as directly network reachable.
* **Local lower-privilege trigger concern: +1**. In some deployments a lower-privileged local component may be able to provoke WLAN firmware recovery while shutdown is in progress, so PR:L is defensible for paranoid triage.
* Conservative full-admin penalty is not applied in the paranoid score because the relevant attacker model may be a reduced-privilege local process or service influencing SSR timing, not full host root.

Not awarded:

* **No strong LPE plausibility +2**. The patch does not show attacker-controlled reclaim, object replacement, callback control, arbitrary write, or type confusion.
* **No remote reachable +2**. The affected path is shutdown plus firmware recovery, not normal packet processing.
* **No strong memory corruption +2**. The evidence supports a lifetime/race teardown bug and NULL dereference, not a demonstrated strong corruption primitive.

## 3. Reachability analysis

Typical triggering requires a PCI/MHI-based ath11k device and a reboot or PCI shutdown overlapping with WLAN firmware crash recovery. In normal deployments, reboot and device teardown require administrative control, so the conservative reachability is local privileged. The paranoid case considers that SSR can be firmware-mediated and that a local lower-privileged service or user may be able to influence firmware crash recovery timing on affected WLAN hardware. AHB-based ath11k devices are explicitly not affected in the normal SSR reset_work flow. The path is hardware-specific and not directly reachable through ordinary network packets.

Call-site confidence: **high**, because the commit message identifies both racing paths and the patch shows synchronization in the RDDM callback plus cancellation of reset_work and dump_work before ath11k_pci_power_down.

## 4. Severity interpretation

This behaves more like **Actionable Moderate** than ordinary Low because it is a real teardown race involving DMA-backed MHI resources and a demonstrated kernel crash. It is not a strong Important candidate on the conservative evidence because practical exploitation beyond DoS is not demonstrated and the normal trigger depends on reboot/shutdown privileges plus a timing window. The paranoid score keeps it above auto-close threshold due to lifetime corruption around device DMA teardown, but does not upgrade it to a strong privilege-escalation case.

## 5. One-sentence report phrase

A race between ath11k PCI shutdown and firmware SSR recovery can cause overlapping MHI teardown of DMA-backed contexts, leading to a NULL pointer dereference and kernel crash, with practical reachability mainly limited to PCI/MHI ath11k devices during reboot or device shutdown.

## 6. Manual review recommendation

**MANUAL CHECK REQUIRED**

Reason: this is a race in privileged device teardown involving DMA-backed resource lifetime, and while the demonstrated impact is DoS, the overlap of async recovery work and shutdown teardown is sensitive enough to require manual review rather than auto-close.

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

Patch: wifi: ath11k: cancel SSR work items during PCI shutdown [ Upstream
Commit: 53dd29e8aeb2a1b5f079178551836b85fc6b53df
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=53dd29e8aeb2a1b5f079178551836b85fc6b53df

Changed files:
  drivers/net/wireless/ath/ath11k/mhi.c
  drivers/net/wireless/ath/ath11k/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=53dd29e8aeb2a1b5f079178551836b85fc6b53df

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

The original Linux kernel CVE announcement for CVE-2026-74407 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74407

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:L/I:L/A:H
  The Best / paranoid CVSS score: 5.8

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: 3
  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: NO
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).