[CVE-2026-68408][LOW] wifi: cfg80211: convert pmsr_free_wk to wiphy_work to fix deadlock [ Upstream

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

CVE: CVE-2026-68408
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: wifi: cfg80211: convert pmsr_free_wk to wiphy_work to fix deadlock [ Upstream
Commit: 21512b5f7a74fd18c996c22e6854efe57d570816
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=21512b5f7a74fd18c996c22e6854efe57d570816
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68408
Analysis date: Mon, 10 Aug 2026 19:06:11 -0400
ActionableScore: 2
ActionableScore lower bound: 1
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-2026-68408 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68408

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-2026-68408	LOW	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:N/I:N/A:H';CWE-667;*CWE-833;CWE-362;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '4.7';DESCR 'A deadlock in the wifi cfg80211 PMSR cleanup path can occur when pmsr_free_wk is queued after a PMSR owning netlink socket is closed while interface teardown runs under wiphy_lock. The teardown path can wait in cancel_work_sync while holding wiphy_lock, and the queued work item can block while trying to acquire the same wiphy_lock before abort processing. This can stall cfg80211 teardown or leave operations and cause a local denial of service for the wireless subsystem. For the CVSS the PR:L is used in the paranoid score because a local user may be able to own or close a PMSR netlink session while a privileged network manager or teardown path brings the interface down. The issue is not directly network reachable and there is no evidence of memory corruption, information disclosure, or privilege escalation.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 2)  SKIP CVE-2026-68408 UNKNOWN SKIP The Fixes patch not applied yet, so unlikely that actual: 6dccbc9f3e1d38565dff7730d2b7d1e8b16c9b09 YES  NO NO unknown 	MAYBE	REMOTE DEADLOCK INIT  DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3	-	-	checked

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

ActionableScore=2
ActionableScoreLower=1

1. ActionableScore
* Conservative score: 1
* Paranoid score: 2
* Final recommended bucket: **Ordinary Moderate / Low-like**::

2. Signal breakdown
* Reliable kernel stall / DoS: +1. The patch fixes a real deadlock between `cancel_work_sync()` under `wiphy_lock` and work that also tries to acquire `wiphy_lock`.
* Broad/common subsystem: +1. cfg80211 is common on WiFi-capable systems, but the affected PMSR path is not a central packet-processing path.
* Hard or unreliable race / timing required: -1. Triggering requires overlap between PMSR netlink socket release and interface teardown.
* Privileged or assisted teardown path: -1 conservative. Interface teardown is typically controlled by CAP_NET_ADMIN or a privileged network manager, although the PMSR owner may be less privileged in some deployments.
* Paranoid local trigger: +1. If an unprivileged local user can create/own the PMSR session while a system network manager tears the interface down, practical PR may be closer to local low privilege.

3. Reachability analysis
This is local only and not network-triggerable by WiFi traffic. A realistic trigger needs a PMSR session release and concurrent wireless interface teardown or leave path. Typical direct control of teardown requires CAP_NET_ADMIN, but desktop or managed systems may allow an unprivileged user process to participate indirectly through netlink session ownership while privileged network management performs teardown. Namespaces only matter if wireless device control is delegated, which is uncommon for normal unprivileged containers.

4. Severity interpretation
This behaves like an ordinary Moderate local DoS. The patch shows a lock-ordering deadlock, not UAF, OOB access, double free, type confusion, stale callback control, information disclosure, or privilege escalation. Theoretical impact is a stuck cfg80211 teardown path or wireless subsystem hang, while realistic exploitation evidence supports availability impact only.

5. One-sentence report phrase
A cfg80211 PMSR cleanup deadlock can occur when PMSR release work races with wireless interface teardown under `wiphy_lock`, allowing a local user or local privileged network-management flow to stall wireless teardown and cause a local DoS.

6. Manual review recommendation
NO MANUAL CHECK NEEDED. The issue is a constrained local deadlock with no memory corruption or privilege-escalation primitive shown, so it can be auto-closed or handled as non-urgent unless the product delegates WiFi management to untrusted users.

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

Patch: wifi: cfg80211: convert pmsr_free_wk to wiphy_work to fix deadlock [ Upstream
Commit: 21512b5f7a74fd18c996c22e6854efe57d570816
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=21512b5f7a74fd18c996c22e6854efe57d570816

Changed files:
  include/net/cfg80211.h
  net/wireless/core.c
  net/wireless/core.h
  net/wireless/pmsr.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=21512b5f7a74fd18c996c22e6854efe57d570816

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

The original Linux kernel CVE announcement for CVE-2026-68408 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68408

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:N/I:N/A:H
  The Best / paranoid CVSS score: 4.7

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: 1
  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).