[CVE-2026-98339][MODERATE REGULAR] wifi: cfg80211: don't filter by BSS type when removing stale entries [ Upstream

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

CVE: CVE-2026-98339
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: wifi: cfg80211: don't filter by BSS type when removing stale entries [ Upstream
Commit: 6ef87a853327434ae1cd9c5a2c27a557fb4047fc
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=6ef87a853327434ae1cd9c5a2c27a557fb4047fc
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98339
Analysis date: Sat, 10 Oct 2026 07:36:44 -0400
ActionableScore: 4
ActionableScore lower bound: 3
Actionable bucket: Borderline / manual review recommended
Manual review required: YES

Summary:
A rogue AP can cause cfg80211 to retain a conflicting BSS entry during an associated channel switch, triggering WARN_ON during BSS rehash and potentially causing a kernel panic on systems configured with panic_on_warn.

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

The original Linux kernel CVE announcement for CVE-2026-98339 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98339

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 REGULAR
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-2026-98339	MODERATE	https://www.kernelcve.org/list/?q=CVE-2026-98339 CHECK WITH IMPACT FROM ORIG NN MODERATE | AEGIS IMPACT MODERATE_KPANIC AEGIS_AS=1 LEGACY=MODERATE RESULT=DIFF (independent Legacy and Aegis differ; FINAL: MODERATE, Aegis: MODERATE_KPANIC)	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H';CWE-697;*CWE-20;CWE-755;Other CVSS 'AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '5.3';DESCR 'A logic error in cfg80211_update_assoc_bss_entry can leave a stale BSS entry in the rbtree because removal candidates are filtered by the current connection BSS type. If an associated AP changes channel and a colliding entry advertises a different capability type such as IBSS, cfg80211_rehash_bss can encounter the retained entry and trigger WARN_ON. A rogue AP or controlled wireless device within radio range may be able to create these conditions, so the issue is network adjacent rather than reachable through an arbitrary routed network. For the CVSS the PR:N value is used because the attacker does not need an account or local execution on the affected host and only needs control of the relevant wireless peer. Attack complexity is high because association state, channel movement, an existing colliding BSS entry, and a BSS type mismatch must align. The demonstrated impact is disruption of wireless state and a kernel warning. On systems configured with panic_on_warn the warning may become a kernel crash and denial of service. No UAF, OOB access, or other memory corruption primitive is demonstrated, so confidentiality and integrity remain unaffected.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline / manual review recommended (with actual score 4)	MAYBE	REMOTE DANGER SYZBOT  DECREASED_TO_MODERATEREG_BASED_ON_FALSEPOSCHECKOFKP	-	-	checked

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

ActionableScore=4
ActionableScoreLower=3
PrimitiveClass=CLASS_C
RealUAF=NO
HostAdminRequired=NO
NamespaceScopedPrivilege=NO
ImportantCandidate=NO
ManualReview=RECOMMENDED
AutoDowngradeAllowed=YES
RequiresHostUID0=NO
AuthorizationDecisionBypass=NO
ProtectedResourceImpact=NONE
B4PendingReview=NO
B4PendingConfirmed=NO

## 1. ActionableScore

* Raw conservative score: 3
* Conservative score: 3
* Raw paranoid score: 4
* Paranoid score: 4
* No floor or cap was applied.
* Final recommended bucket: **Borderline / manual review recommended**::

## 2. Signal breakdown

Conservative signals:

* +2 Remote or network-adjacent trigger. The commit explicitly states that a rogue AP or wireless device can trigger the conflicting BSS state.
* +1 Broad and realistically exercised subsystem. cfg80211 association, scanning, and AP channel-switch handling are common Wi-Fi operations.
* +0 WARN_ON consequence. A warning alone is not counted as a reliable kernel crash.
* 0 negative points. AC:H-like state requirements are not treated as a hard timing race because no narrow or uncontrollable race window is established.

Paranoid addition:

* +1 Conditional strong DoS. If the affected system uses panic_on_warn, the reachable WARN_ON can terminate the host kernel.

Important non-awarded signals:

* No UAF or post-lifetime access is established.
* The stale BSS entry is logically obsolete but is not shown to reference freed storage.
* No OOB read, OOB write, controlled overwrite, arbitrary write, or controlled reclaim is demonstrated.
* No list or rbtree memory corruption after the collision is established. The supplied evidence demonstrates collision detection through WARN_ON.
* No additional availability point is awarded for the same conditional panic.
* No confidentiality, integrity, authorization-bypass, or privilege-escalation primitive is established.
* B5-R does not apply because there is no confirmed retry-accumulated heap OOB write or subsequent consumption of corrupted state.
* B3-PENDING does not apply because no shared-backing write exists.
* B4-PENDING does not apply because no mandatory authorization decision changes from DENY to ALLOW.

## 3. Reachability analysis

A rogue AP or another controlled wireless device within radio range can advertise a conflicting BSS type and participate in a channel switch while the victim has an existing colliding BSS entry. The attacker does not need local execution, host UID 0, a namespace capability, or host-administrator privileges.

The trigger requires an associated wireless connection, a channel transition, an existing matching BSS-tree key, and a capability-type mismatch. These are state prerequisites rather than a demonstrated hard timing race.

No prior attacker-controlled privileged setup is established. An operational Wi-Fi interface and association are environmental prerequisites, but Wi-Fi hardware is common and does not justify a rare-hardware penalty. Network namespaces and delegated capabilities are not part of the trigger.

## 4. Primitive and severity interpretation

The exact primitive is an invalid BSS-tree state caused by failing to remove a logically conflicting entry before rehashing the associated BSS. The later rehash detects an equal comparison and reaches WARN_ON.

This is Class C because the demonstrated behavior is an invalid-state warning with a configuration-dependent DoS outcome. It is not a real UAF, active post-lifetime object use, authorization bypass, or confirmed tree-memory corruption primitive.

The practical consequence is a kernel warning and possible disruption of wireless state. Kernel panic is supported only for configurations such as panic_on_warn. Stronger consequences such as arbitrary kernel memory modification, information disclosure, or privilege escalation are unsupported.

ImportantCandidate is NO because no independently useful corruption or security-boundary primitive survives after excluding the warning or conditional crash. AutoDowngradeAllowed is YES because the established issue remains a constrained network-adjacent invalid-state and DoS case.

## 5. One-sentence report phrase

A rogue AP can cause cfg80211 to retain a conflicting BSS entry during an associated channel switch, triggering WARN_ON during BSS rehash and potentially causing a kernel panic on systems configured with panic_on_warn.

## 6. Manual review recommendation

MANUAL CHECK RECOMMENDED

The network-adjacent trigger and possible panic warrant confirmation of the exact cfg80211_rehash_bss behavior, but the supplied evidence does not establish memory corruption or an Important-grade primitive.

## 7. Call-site confidence

Call-site confidence: medium

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

Patch: wifi: cfg80211: don't filter by BSS type when removing stale entries [ Upstream
Commit: 6ef87a853327434ae1cd9c5a2c27a557fb4047fc
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=6ef87a853327434ae1cd9c5a2c27a557fb4047fc

Changed files:
  net/wireless/scan.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=6ef87a853327434ae1cd9c5a2c27a557fb4047fc

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

The original Linux kernel CVE announcement for CVE-2026-98339 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98339

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:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
  The Best / paranoid CVSS vector: AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS score: 5.3

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: 4

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 REGULAR

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).