[CVE-2026-98421][LOW] wifi: mac80211: require a peer station for TDLS setup confirm [ Upstream

[CVE-2026-98421][LOW] wifi: mac80211: require a peer station for TDLS setup confirm [ Upstream

[AL-KERNEL]

CVE: CVE-2026-98421
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: wifi: mac80211: require a peer station for TDLS setup confirm [ Upstream
Commit: 6bae6ef511a29ef12ab969adeea691067d4d5d74
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=6bae6ef511a29ef12ab969adeea691067d4d5d74
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98421
Analysis date: Wed, 14 Oct 2026 22:38:00 -0400
ActionableScore: 1
ActionableScore lower bound: 0
Actionable bucket: Ordinary Moderate
Manual review required: NO

Summary:
A local TDLS management request could submit a setup confirmation for a missing peer and trigger WARN_ON_ONCE during frame construction, with a conditional kernel panic only on systems configured with panic_on_warn.

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

The original Linux kernel CVE announcement for CVE-2026-98421 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98421

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-2026-98421	LOW	https://www.kernelcve.org/list/?q=CVE-2026-98421 CHECK WITH IMPACT FROM ORIG NN LOW | AEGIS IMPACT LOW AEGIS_AS=0 LEGACY=LOW RESULT=SAME (legacy and Aegis reconciliation agree; DECISION: both LOW)	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H';*CWE-20;CWE-754;CWE-670;Other CVSS 'AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '5.5';DESCR 'mac80211 accepts a TDLS setup confirmation even when the requested peer station does not exist or is not marked as a TDLS station. The invalid state reaches management frame construction and triggers WARN_ON_ONCE because the required station context is missing. The demonstrated effect is a warning and failed operation, but systems configured with panic_on_warn can turn the warning into a kernel panic and system wide denial of service. For the CVSS the PR:L value is used for the paranoid score because access may be delegated to a network service, container root, or a process with limited network administration capabilities. The base scenario normally requires CAP_NET_ADMIN and is therefore closer to PR:H. The issue is locally triggered through the mac80211 or nl80211 control path and is not directly reachable through received wireless or TDLS traffic. No race, use after free, out of bounds access, or other memory corruption primitive is demonstrated. Automated impact decision path. The original SimpleNet classifier selected MODERATE_KPANIC. The primary LLM estimated paranoid CVSS 5.5 and the production ActionableScore returned 1 with recommendation Ordinary Moderate. The production rules then evaluated CVSS thresholds and ActionableScore thresholds. Recorded rule transitions were CVSS and initial triage stage MODERATE_KPANIC to MODERATE because the CVSS score, vector or bug class threshold rule was applied. ActionableScore thresholds stage MODERATE to LOW because the ActionableScore threshold rule was applied. final reconciliation stage LOW to LOW because KP specialist did not establish a qualifying panic. The legacy KP specialist has no review artifact for this run. The legacy FD or DH downgrade specialist has no review artifact for this run. Exact triggered rule markers were DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH and DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3 and KPANIC_UNSUPPORTED_REMOVED. The independent weaker Aegis shadow evaluated CVSS 4.5 and ActionableScore 0 with primitive class CLASS_C and manual review NO. Its independently reconciled impact was LOW. The shadow agreed with the final production impact and aggregation did not change that impact. The final reported impact is LOW.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 1)	MAYBE	REMOTE INIT SYZBOT DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3 KPANIC_UNSUPPORTED_REMOVED	-	-	checked

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

ActionableScore=1
ActionableScoreLower=0
PrimitiveClass=CLASS_C
RealUAF=NO
HostAdminRequired=UNKNOWN
NamespaceScopedPrivilege=UNKNOWN
ImportantCandidate=NO
ManualReview=NO
AutoDowngradeAllowed=YES
RequiresHostUID0=UNKNOWN
AuthorizationDecisionBypass=NO
ProtectedResourceImpact=NONE
B4PendingReview=NO
B4PendingConfirmed=NO

## 1. ActionableScore

* Raw conservative score: 0.
* Conservative score: 0. No floor or cap applied.
* Raw paranoid score: 1.
* Paranoid score: 1. No floor or cap applied.
* Final recommended bucket: **Ordinary Moderate**::

The paranoid score accounts only for a conditional kernel panic when `panic_on_warn` is enabled.

## 2. Signal breakdown

Conservative signals:

* +0 invalid-state warning. The unsupported TDLS setup-confirm reaches frame construction without an existing TDLS peer and triggers `WARN_ON_ONCE`.
* +0 ordinary `WARN_ON_ONCE`. No fatal consequence is demonstrated under normal configuration.
* +0 privilege penalty. The complete nl80211 permission and namespace boundary is not visible, so host-admin privilege is not assumed.

Paranoid signals:

* +1 conditional strong DoS. The supplied context establishes that `panic_on_warn` can convert the warning into a kernel panic.

Important non-awarded signals:

* No UAF, OOB access, stale lifetime use, refcount mutation, or heap corruption is established.
* No controlled reclaim, arbitrary write, information disclosure, or privilege escalation is demonstrated.
* No remote reachability is established. Received TDLS traffic does not directly invoke this local management operation.
* No authorization bypass exists. The new check validates protocol and station state rather than restoring an access-control decision.
* No extra availability point is awarded because a conditional panic is the only potentially fatal consequence.
* B5-R does not apply because there is no retry-accumulated OOB write.
* B3-PENDING does not apply because there is no shared-backing write.
* B4-PENDING does not apply because no mandatory authorization guard changes from DENY to ALLOW.

## 3. Reachability analysis

The trigger is a local mac80211 or nl80211 TDLS management request using `WLAN_TDLS_SETUP_CONFIRM` for a missing or non-TDLS peer. It is not directly triggered by an incoming wireless frame.

The supplied patch does not expose the complete netlink permission checks. Access may require `CAP_NET_ADMIN`, but it is unresolved whether this must be host-admin-equivalent, can be delegated, or can be exercised entirely within an attacker-controlled user and network namespace. Therefore both host-admin and namespace-scoped privilege are `UNKNOWN`, with no scoring penalty or unprivileged bonus.

A configured mac80211 wireless interface is required. This is not treated as rare hardware. There is no race or timing requirement.

## 4. Primitive and severity interpretation

The exact defect is missing state validation before constructing a TDLS setup-confirm frame. The requested peer may not exist or may not be marked as a TDLS station, causing an internal warning.

This is neither fixed stale storage nor an active structured-object UAF. No object lifetime has ended, no dangling reference is consumed, and no repeated release or refcount operation exists.

The demonstrated behavior is invalid-state processing followed by `WARN_ON_ONCE`, making this `CLASS_C`. The practical result is normally a warning and failed operation. Kernel panic is conditional on `panic_on_warn`.

There is no useful primitive beyond the warning or conditional crash. Consequently, this is not an Important candidate and automatic downgrade is allowed.

## 5. One-sentence report phrase

A local TDLS management request could submit a setup confirmation for a missing peer and trigger WARN_ON_ONCE during frame construction, with a conditional kernel panic only on systems configured with panic_on_warn.

## 6. Manual review recommendation

NO MANUAL CHECK NEEDED

The patch establishes only missing state validation and a warning path, without memory corruption, authorization bypass, remote trigger, or unresolved lifetime primitive.

## 7. Call-site confidence

Call-site confidence: medium

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

Patch: wifi: mac80211: require a peer station for TDLS setup confirm [ Upstream
Commit: 6bae6ef511a29ef12ab969adeea691067d4d5d74
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=6bae6ef511a29ef12ab969adeea691067d4d5d74

Changed files:
  net/mac80211/tdls.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=6bae6ef511a29ef12ab969adeea691067d4d5d74

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

The original Linux kernel CVE announcement for CVE-2026-98421 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98421

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:L/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS score: 5.5

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: 0
  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).