[CVE-2026-98705][MODERATE REGULAR] wifi: mac80211: account proxy paths against the mesh path limit

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

CVE: CVE-2026-98705
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: wifi: mac80211: account proxy paths against the mesh path limit
Commit: df072db65fdaa34ad15e1d66fc06a53e3e97f778
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=df072db65fdaa34ad15e1d66fc06a53e3e97f778
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98705
Analysis date: Sat, 24 Oct 2026 07:02:28 -0400
ActionableScore: 3
ActionableScore lower bound: unknown
Actionable bucket: Borderline / manual review recommended
Manual review required: YES

Summary:
Nearby mesh proxy-path churn can underflow path accounting and bypass the 1024-entry path-table resource limit, potentially increasing memory and CPU consumption without demonstrated memory corruption.

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

The original Linux kernel CVE announcement for CVE-2026-98705 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98705

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.

======================================================================
AL-KERNEL CLASSIFICATION RESULT
======================================================================

CVE-2026-98705	MODERATE	https://www.kernelcve.org/list/?q=CVE-2026-98705 CHECK WITH IMPACT FROM ORIG NN MODERATE | AEGIS IMPACT MODERATE_KPANIC AEGIS_AS=1 LEGACY=MODERATE RESULT=DIFF (final 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:L/PR:N/UI:N/S:U/C:N/I:N/A:H';CWE-682;**CWE-400;CWE-770;Other CVSS 'AV:A/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '6.5';DESCR 'Incorrect accounting of the shared mesh path quota lets proxy path removal decrement a counter that was never incremented when the proxy path was added. Repeated proxy path creation and expiration can drive the counter below the real number of installed paths and allow later additions to exceed the 1024 path limit. The demonstrated primitive is resource limit bypass and potential memory or CPU exhaustion. There is no evidence of UAF, OOB access, information disclosure, or an arbitrary write. For the CVSS the PR:N value in the paranoid vector covers an open mesh where a nearby radio attacker can participate without credentials, while PR:L in the base vector represents a protected mesh that requires valid peer access. Automated impact decision path. The original SimpleNet classifier selected MODERATE_KPANIC. The primary LLM estimated paranoid CVSS 6.5 and the production ActionableScore returned 3 with recommendation Borderline / manual review recommended. The production rules then evaluated CVSS thresholds and ActionableScore thresholds. Recorded rule transitions were ActionableScore thresholds stage MODERATE_KPANIC to MODERATE because the ActionableScore threshold rule was applied. 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_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN4 and V41_INHERITED_KPANIC_PROMOTION_BLOCKED and MANUAL_REVIEW_REQUIRED. The independent weaker Aegis shadow evaluated CVSS 2.5 and ActionableScore 1 with primitive class CLASS_C and manual review REQUIRED. Its independently reconciled impact was MODERATE_KPANIC. The models disagreed but the aggregation rules retained the production result. The final reported impact is MODERATE.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline / manual review recommended (with actual score 3)	MAYBE	REMOTE SIMPLEFIX  DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN4 V41_INHERITED_KPANIC_PROMOTION_BLOCKED MANUAL_REVIEW_REQUIRED	-	-	checked

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

ActionableScore=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 base score: 3.
* Conservative score: 3; no floor or cap applied.
* Raw paranoid score: 3.
* Paranoid score: 3; stronger consequences are not sufficiently evidenced.
* Final recommended bucket: **Borderline / manual review recommended**::

2. Signal breakdown

* +2 — Adjacent network reachability: supplied evidence grounds repeated proxy-path creation and expiration by a participating nearby mesh peer.
* +1 — Concrete resource-limit/accounting bypass: uncharged proxy paths are later decremented, driving `mpaths` below the installed-path count and defeating the shared 1024-entry limit.
* +0 — Strong DoS not awarded: memory or CPU exhaustion is plausible, but neither host-wide exhaustion nor a reliable crash is demonstrated.
* +0 — No corruption primitive: the changed state is an atomic quota counter; no heap OOB, UAF, invalid pointer, or overwrite is shown.
* +0 — No authorization bypass: this is quota enforcement, not a mandatory credential or capability guard changing DENY to ALLOW.
* No rarity, timing, or privilege penalty: the evidence does not establish a difficult race, host-admin trigger requirement, or sufficiently rare deployment.

NEW52 B5-R does not apply: there is no confirmed heap/slab OOB write or later consumption of OOB-corrupted descriptors. NEW53 and B4-PENDING are also inapplicable.

3. Reachability analysis

A nearby mesh participant can influence proxy-path churn after a mesh interface has been configured. An open mesh may permit an unauthenticated radio peer; a protected mesh requires peer credentials, but neither model requires host-administrator powers for the subsequent churn. Initial mesh-interface provisioning is prior host-side setup. No user-namespace or namespace-scoped capability chain is involved, and no special timing race is shown.

4. Primitive and severity reading

The exact defect is negative quota accounting: proxy entries consume no slot when added but return a slot when freed. The corrupted counter is later read by `mesh_path_add()`, permitting the installed path count to exceed `MESH_MAX_MPATHS`.

This is passive accounting/resource-state corruption, classified CLASS_C. The shown effect is limit bypass and potentially accumulating path-table resource consumption. Host-wide exhaustion, panic, memory corruption, confidentiality loss, integrity compromise, and privilege escalation remain unproven. ImportantCandidate is therefore NO, and ordinary Moderate downgrade remains permissible after review.

5. One-sentence report phrase

Nearby mesh proxy-path churn can underflow path accounting and bypass the 1024-entry path-table resource limit, potentially increasing memory and CPU consumption without demonstrated memory corruption.

6. Manual review advice

MANUAL CHECK RECOMMENDED

Confirm practical path accumulation, cleanup behavior, and whether a reachable workload can cause host-wide resource exhaustion.

7. Call-site confidence

Call-site confidence: high

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

Patch: wifi: mac80211: account proxy paths against the mesh path limit
Commit: df072db65fdaa34ad15e1d66fc06a53e3e97f778
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=df072db65fdaa34ad15e1d66fc06a53e3e97f778

Commit description:

Proxy-path churn can drive the interface path counter negative and let
later mesh path additions exceed MESH_MAX_MPATHS.

mesh_path_free_rcu() decrements the interface mpaths counter for entries
from both the mesh and proxy path tables, but mpp_path_add() never
reserves a slot in that counter. Removing or expiring a proxy path
therefore returns a slot that was never charged.

mesh_path_add() uses the same counter to enforce MESH_MAX_MPATHS, so once
it falls below the number of installed paths the limit no longer holds.

Reserve the shared quota before allocating a proxy path and release it on
every unsuccessful addition. Mesh and proxy paths now share one
1024-entry budget, so mpp_path_add() can return -ENOSPC at that limit.

Fixes: ece1a2e ("mac80211: Remove mesh paths when an interface is removed")
Cc: stable@vger.kernel.org
Assisted-by: LLM sparse kasan
Signed-off-by: Zhao Li <enderaoelyther@gmail.com>
Link: https://patch.msgid.link/20260916113649.28315-3-enderaoelyther@gmail.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Changed files:
  net/mac80211/mesh_pathtbl.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=df072db65fdaa34ad15e1d66fc06a53e3e97f778

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

The original Linux kernel CVE announcement for CVE-2026-98705 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98705

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:L/PR:L/UI:N/S:U/C:N/I:N/A:L
  The Best / paranoid CVSS vector: AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS score: 6.5

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: unknown
  Paranoid ActionableScore: 3

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).