[CVE-2026-64515][MODERATE 7.0] wifi: mac80211: fix MLE defragmentation [ Upstream

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

CVE: CVE-2026-64515
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: YES
Patch: wifi: mac80211: fix MLE defragmentation [ Upstream
Commit: 1f573e17bcb7275ddd1c8f47f46ae0faf0e902a4
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=1f573e17bcb7275ddd1c8f47f46ae0faf0e902a4
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-64515
Analysis date: Sat, 25 Jul 2026 15:14:48 -0400
ActionableScore: 5
ActionableScore lower bound: 4
Actionable bucket: Actionable Moderate at minimum
Manual review required: YES

Summary:
A crafted adjacent WiFi management frame can cause mac80211 MLE defragmentation to use mismatched element and container bounds, potentially leading to a bounded heap overread and WiFi parsing failure or DoS.

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ABOUT THIS REPORT
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The original Linux kernel CVE announcement for CVE-2026-64515 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-64515

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 7.0
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-2026-64515	MODERATE	CHECK WITH IMPACT FROM ORIG NN MODERATE	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:A/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H';CWE-125;CWE-126;*CWE-20;Other CVSS 'AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '6.4';DESCR 'mac80211 MLE defragmentation can use a pointer to a defragmented copy while still using the original element container boundaries when reconf or EPCS MLE data is located inside a non transmitted profile. A crafted adjacent WiFi management frame can make the parser search fragments in the wrong buffer and potentially read past the intended heap object into the defragmentation scratch buffer. For the CVSS the PR:N is used because a sender in radio range does not need a local account on the target, but the attack is AV:A rather than AV:N because it requires WiFi adjacency. The realistic impact is parsing failure or limited denial of service, while the paranoid score keeps C:L/I:L/A:H because the bug is an out of bounds read in kernel heap parsing and should be manually reviewed for hidden state corruption or crash paths.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Actionable Moderate at minimum (with actual score 5)	YES	REMOTE  KPANIC INCREASED_TO_MODERATE7_FROM_MODERATE_BASED_ON_GUESSCVSS	YES	NO	checked

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ACTIONABLESCORE ANALYSIS
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ActionableScore=5
ActionableScoreLower=4

## 1. ActionableScore

* Conservative score: 4
* Paranoid score: 5
* Final recommended bucket: **Actionable Moderate at minimum**::

## 2. Signal breakdown

* Remote reachable / network-triggerable: +2. Crafted WiFi management frames can reach mac80211 parsing from an adjacent radio attacker.
* Availability impact realistic: +1. The realistic outcome is parsing failure or limited DoS in the WiFi management-frame parsing path.
* Broad/default/common subsystem: +1. mac80211 is a common Linux WiFi subsystem and management-frame parsing is a normal receive path.
* Paranoid only, weak/indirect corruption candidate: +1. The patch context describes a possible heap overread due to mismatched element pointer and container bounds, but not an OOB write, UAF, reclaim primitive, or controlled overwrite.

No strong memory corruption bonus is applied. The described overrun is read-side and likely bounded into the defragmentation scratch buffer. No confidentiality or integrity bonus is counted conservatively because no user-visible disclosure or write primitive is shown.

## 3. Reachability analysis

An attacker in WiFi radio range may trigger the path by sending crafted management frames containing reconf or EPCS MLE data in a non-transmitted profile. No local account on the target is required, so the practical privilege requirement is none, but the vector is adjacent network rather than ordinary IP network. The affected path depends on WiFi MLE parsing and therefore on hardware, driver, and 802.11be or related multi-link feature exposure. Namespaces do not materially reduce the attacker requirement because the trigger is over the air.

Call-site confidence: high. The patch shows the relevant parser state, stored MLE pointers, container start and length tracking, and the corrected call to cfg80211_defragment_element.

## 4. Severity interpretation

This behaves more like Actionable Moderate than ordinary Moderate because it is adjacent-network reachable kernel heap parsing with a concrete OOB-read candidate. It is not a Strong Important candidate based on the provided evidence because the patch does not show UAF, OOB write, attacker-controlled overwrite, object reuse, callback control, or a demonstrated privilege-escalation path. Theoretical memory-corruption concern exists only in the paranoid sense and should be manually reviewed, but the realistic impact appears to be limited parsing failure or DoS.

## 5. One-sentence report phrase

A crafted adjacent WiFi management frame can cause mac80211 MLE defragmentation to use mismatched element and container bounds, potentially leading to a bounded heap overread and WiFi parsing failure or DoS.

## 6. Manual review recommendation

MANUAL CHECK REQUIRED

Reason: adjacent-network reachable kernel heap parsing bugs are historically easy to under-triage, and this one has a concrete OOB-read condition even though the currently visible primitive appears constrained and not clearly exploitable for privilege escalation.

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

Patch: wifi: mac80211: fix MLE defragmentation [ Upstream
Commit: 1f573e17bcb7275ddd1c8f47f46ae0faf0e902a4
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=1f573e17bcb7275ddd1c8f47f46ae0faf0e902a4

Changed files:
  net/mac80211/parse.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=1f573e17bcb7275ddd1c8f47f46ae0faf0e902a4

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

The original Linux kernel CVE announcement for CVE-2026-64515 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-64515

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:L/I:L/A:H
  The Best / paranoid CVSS score: 6.4

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: 4
  Paranoid ActionableScore: 5

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: YES
Published priority for this report (same as in Subject): MODERATE 7.0

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).