[CVE-2026-98823][IMPORTANT] wifi: cfg80211: preserve hidden-group beacon IE ownership [ Upstream

[CVE-2026-98823][IMPORTANT] wifi: cfg80211: preserve hidden-group beacon IE ownership [ Upstream

[AL-KERNEL]

CVE: CVE-2026-98823
Priority: IMPORTANT
AL-KERNEL base severity: IMPORTANT
KPANIC flag: NO
Patch: wifi: cfg80211: preserve hidden-group beacon IE ownership [ Upstream
Commit: 49b66110a08e4f926f6393e938f226de2750a08b
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=49b66110a08e4f926f6393e938f226de2750a08b
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98823
Analysis date: Sat, 24 Oct 2026 08:45:49 -0400
ActionableScore: 7
ActionableScore lower bound: 6
Actionable bucket: Actionable Moderate / Strong Important candidate requiring manual review
Manual review required: YES

Summary:
Nearby attacker-influenced hidden-BSS scan merging can create duplicate ownership of beacon IEs, leading to a dangling pointer and later heap double free.

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

The original Linux kernel CVE announcement for CVE-2026-98823 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98823

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: IMPORTANT
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
======================================================================

CVE-2026-98823	IMPORTANT	https://www.kernelcve.org/list/?q=CVE-2026-98823 CHECK WITH IMPACT FROM ORIG NN IMPORTANT | AEGIS IMPACT MODERATE_KPANIC AEGIS_AS=3 LEGACY=IMPORTANT RESULT=DIFF INDEPENDENT_LEGACY=IMPORTANT INDEPENDENT_RESULT=DIFF TEMP_KPANIC_MERGE=IMPORTANT_WINS_DISAGREEMENT PRE_MERGE_LEGACY=IMPORTANT (final Legacy and Aegis differ; FINAL: IMPORTANT, 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:H/I:H/A:H';*CWE-416;CWE-415;*CWE-664;Other CVSS 'AV:A/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H';BEST CVSS score: '7.5';DESCR 'cfg80211 could copy borrowed beacon IEs from a hidden group probe response entry into an associated BSS entry, giving one allocation two apparent owners. Releasing the group beacon entry can leave the associated entry with a dangling pointer and its later release can cause a second free, producing a kernel use after free and double free condition. For the CVSS the PR:N value is selected because a nearby attacker controlling WiFi management traffic or a malicious access point does not need an account or privileges on the victim. AV:A and AC:H reflect that exploitation requires local radio proximity and a specific hidden group, association, scan merge, and channel switch lifecycle. Impact is at least denial of service through a kernel crash and may include confidentiality or integrity impact because the demonstrated ownership error can corrupt kernel heap state. Automated impact decision path. The original SimpleNet classifier selected IMPORTANT. The primary LLM estimated paranoid CVSS 7.5 and the production ActionableScore returned 7 with recommendation Actionable Moderate / Strong Important candidate requiring manual review. The production rules then evaluated CVSS thresholds and ActionableScore thresholds. Recorded rule transitions were final reconciliation stage IMPORTANT to IMPORTANT because KP specialist did not establish a qualifying panic. The legacy KP specialist produced a review artifact and its decision was processed by the applicable KP rules. The legacy FD or DH downgrade specialist produced a review artifact and its decision was processed by the applicable downgrade and preservation rules. Exact triggered rule markers were TEMP_KPANIC_MERGE_IMPORTANT_WINS and KPANIC_UNSUPPORTED_REMOVED. The independent weaker Aegis shadow evaluated CVSS 1.8 and ActionableScore 3 with primitive class CLASS_B and manual review REQUIRED. Its independently reconciled impact was MODERATE_KPANIC. Cross model aggregation changed the production result under an enabled evidence gated merge rule. The final reported impact is IMPORTANT.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Actionable Moderate / Strong Important candidate requiring manual review (with actual score 7)	MAYBE	REMOTE UAF TEMP_KPANIC_MERGE_IMPORTANT_WINS KPANIC_UNSUPPORTED_REMOVED	-	-	checked

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

ActionableScore=7
ActionableScoreLower=6
PrimitiveClass=CLASS_B
RealUAF=YES
HostAdminRequired=NO
NamespaceScopedPrivilege=NO
ImportantCandidate=YES
ManualReview=REQUIRED
AutoDowngradeAllowed=NO
RequiresHostUID0=NO
AuthorizationDecisionBypass=NO
ProtectedResourceImpact=NONE
B4PendingReview=NO
B4PendingConfirmed=NO

1. ActionableScore

* Raw base score: 6.
* Conservative score: 6; FLOOR 5 is satisfied but does not change the score.
* Raw paranoid score: 7.
* Paranoid score: 7; no cap or floor adjustment.
* Final recommended bucket: **Actionable Moderate / Strong Important candidate requiring manual review**::

2. Signal breakdown

* +2 Real UAF/lifetime violation: two BSS entries acquire ownership of the same `beacon_ies` allocation; releasing the group entry leaves the associated entry dangling.
* +1 Concrete repeated release/free: the first release can free the allocation, the exact aliased pointer survives in the associated entry, and its later release performs a second `kfree`-class lifetime mutation.
* +2 Network reachability: supplied evidence grounds a nearby malicious AP or management-frame sender influencing the hidden-group scan/merge/channel-switch sequence without local credentials.
* +1 Reliable kernel crash/strong DoS: a heap double free plausibly produces allocator detection, corruption, or a fatal kernel fault.
* Paranoid +1: the second free operates on storage whose allocation lifetime has ended and can mutate allocator metadata. This is the specific stale lifetime operation, not generic speculation about reclaim.
* FLOOR 5 applies because the exact allocation survives its first freeing owner and is freed again; it does not alter the base score.
* No controlled reclaim, chosen adjacent victim, arbitrary write, disclosure, or LPE is shown. Structured stale-object leverage and Weak LPE are not separately counted for the same second-free fact. No extra Availability or C/I points are awarded.

3. Reachability analysis

The supported attacker is a radio-adjacent sender controlling relevant WiFi management traffic or a malicious AP. Triggering requires a hidden-group probe-response entry, association/scan-entry merging after a channel switch, and subsequent BSS-entry releases. These are substantial sequence requirements, but no narrow race or unreliable timing is shown, so no AC penalty applies.

The complete path does not require host UID 0, capabilities, or namespace privilege. Ordinary victim WiFi operation is required, but no separate host-admin provisioning is established.

4. Primitive and severity reading

This is an active structured ownership error, not fixed stale storage: borrowed beacon IEs are installed as though independently owned. It is stronger than an ordinary stale cleanup dereference:

A. The associated entry retains a dangling IE pointer after the group owner releases it.

B. Its later release actively frees the same already-freed allocation.

That is a CLASS_B UAF/double-free primitive. Crash and heap lifetime corruption are supported; controlled reuse, directed corruption, confidentiality impact, integrity impact, and privilege escalation remain unproven. The specific second lifetime mutation leaves material exploit leverage unresolved, making this an Important candidate and preventing automatic downgrade.

5. One-sentence report phrase

Nearby attacker-influenced hidden-BSS scan merging can create duplicate ownership of beacon IEs, leading to a dangling pointer and later heap double free.

6. Manual review advice

MANUAL CHECK REQUIRED

The confirmed second free through a dangling ownership alias is a concrete heap-lifetime corruption primitive whose leverage beyond kernel DoS remains unresolved.

7. Call-site confidence

Call-site confidence: medium

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

Patch: wifi: cfg80211: preserve hidden-group beacon IE ownership [ Upstream
Commit: 49b66110a08e4f926f6393e938f226de2750a08b
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=49b66110a08e4f926f6393e938f226de2750a08b

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=49b66110a08e4f926f6393e938f226de2750a08b

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

The original Linux kernel CVE announcement for CVE-2026-98823 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98823

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:L/I:L/A:H
  The Best / paranoid CVSS vector: AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
  The Best / paranoid CVSS score: 7.5

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: 6
  Paranoid ActionableScore: 7

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: IMPORTANT
KPANIC detected for this report: NO
Published priority for this report (same as in Subject): IMPORTANT

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).