[CVE-2026-68470][IMPORTANT] wifi: mac80211: validate extension-frame layout before RX

[CVE-2026-68470][IMPORTANT] wifi: mac80211: validate extension-frame layout before RX

[AL-KERNEL]

CVE: CVE-2026-68470
Priority: IMPORTANT
AL-KERNEL base severity: IMPORTANT
KPANIC flag: YES
Patch: wifi: mac80211: validate extension-frame layout before RX
Commit: 625fc704b19cb48d7d269ad54ffffb4d3bf9c7ed
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=625fc704b19cb48d7d269ad54ffffb4d3bf9c7ed
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68470
Analysis date: Sun, 16 Aug 2026 01:27:16 -0400
ActionableScore: 6
ActionableScore lower bound: 5
Actionable bucket: Actionable Moderate at minimum
Manual review required: YES

Summary:
Malformed 802.11 extension frames can reach mac80211 RX paths before layout validation, allowing a nearby wireless attacker to trigger invalid regular-header field reads and likely cause a kernel or Wi-Fi stack DoS.

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ABOUT THIS REPORT
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The original Linux kernel CVE announcement for CVE-2026-68470 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68470

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
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CVE-2026-68470	IMPORTANT	CHECK WITH IMPACT FROM ORIG NN IMPORTANT	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H';CWE-125;*CWE-20;CWE-1284;Other CVSS 'AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '7.6';DESCR 'A malformed 802.11 extension frame can reach generic mac80211 RX paths before the frame layout is validated. Those paths may read regular header address fields even though extension frames do not provide the same layout, and short S1G beacon extension frames may lack the fixed fields expected by later helpers. A nearby wireless attacker can trigger this over the air by sending crafted extension frames to an affected Wi-Fi receiver, causing invalid or out-of-bounds reads in kernel RX processing and likely a kernel crash or network stack DoS. For the CVSS the PR:N is used because no local account is required when the attacker can transmit frames within radio range. The vector is AV:A rather than AV:N because exploitation requires adjacent Wi-Fi access. Impact is at least denial of service, with paranoid C:L and I:L kept for manual-review sensitivity because wrong address-field reads can affect RX accept and dispatch decisions, but no strong UAF or write primitive is shown.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Actionable Moderate at minimum (with actual score 7)	YES	REMOTE OOB SKB KPANIC 	NO	NO	checked

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ACTIONABLESCORE ANALYSIS
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ActionableScore=6
ActionableScoreLower=5

## 1. ActionableScore

* Conservative score: 5
* Paranoid score: 6
* Final recommended bucket: **Actionable Moderate at minimum**::

## 2. Signal breakdown

Conservative signals:

* Remote or network-triggerable: +2. The trigger is over-the-air crafted 802.11 frames, so it is externally reachable by a nearby wireless attacker, although this is adjacent wireless exposure rather than Internet-routable AV:N.
* Reliable kernel crash or strong DoS: +1. The patch prevents malformed extension frames and short S1G beacon frames from reaching RX paths that read regular 802.11 header fields, which supports a realistic kernel RX parsing crash or wireless stack DoS concern.
* Common networking packet-processing path: +1. The affected code is in mac80211 RX processing.
* Broad/default/common subsystem exposure: +1. mac80211 is a broadly used Linux Wi-Fi subsystem, even if S1G-specific deployments are less common.

Conservative total: 5

Paranoid additional signal:

* Memory corruption, weak or indirect corruption candidate: +1. The bug is best described as invalid or out-of-bounds reads and bogus interpretation of extension-frame layout as regular 802.11 headers. There is no demonstrated write primitive, UAF, reclaim, or callback control, so this is not strong memory corruption.

Paranoid total: 6

Not awarded:

* No privilege escalation plausible bonus. The patch does not show UAF reclaim, overwrite, type confusion, arbitrary write, refcount takeover, or callback control.
* No strong memory corruption bonus. The concrete primitive is read-side layout confusion and bounds validation failure, not OOB write or UAF.
* No Dirty-Pipe-like or ownership/COW signal.
* No local unprivileged trigger signal because the attacker does not need a local account. The exposure is adjacent wireless frame injection.

## 3. Reachability analysis

A nearby attacker with Wi-Fi transmit capability can plausibly trigger the affected RX path by sending malformed 802.11 extension frames or short S1G beacon extension frames to an affected receiver. No local user account on the victim is required. Namespaces and containers are not central to reachability because the attack surface is the wireless receive path, not a local syscall or netlink control interface.

The path is not Internet-routable and should not be scored like AV:N remote TCP/IP exposure. It is adjacent-network exposure requiring radio range and hardware or driver behavior that passes such frames into mac80211. S1G-specific handling is more specialized, but the patch also drops unsupported extension subtypes before generic regular-header processing, so this deserves manual triage rather than auto-close.

## 4. Severity interpretation

This behaves like an actionable Moderate issue rather than a clear Important-class vulnerability. The realistic impact is adjacent-network DoS through malformed Wi-Fi frame parsing. The theoretical concern is limited invalid or out-of-bounds reads and layout confusion in RX dispatch paths, but the patch does not support arbitrary write, UAF, privilege escalation, or a strong confidentiality leak.

The paranoid score is higher because unauthenticated adjacent packet parsing in mac80211 plus layout confusion is historically worth manual review, but the evidence does not justify treating it as a strong LPE or Critical-class memory corruption issue.

## 5. One-sentence report phrase

Malformed 802.11 extension frames can reach mac80211 RX paths before layout validation, allowing a nearby wireless attacker to trigger invalid regular-header field reads and likely cause a kernel or Wi-Fi stack DoS.

## 6. Manual review recommendation

MANUAL CHECK REQUIRED

Reason: this is adjacent-network reachable, unauthenticated at the victim OS level, and involves kernel RX parsing of malformed Wi-Fi frames with potential out-of-bounds reads, but the available patch evidence supports DoS and weak layout-confusion risk rather than proven privilege escalation.

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UPSTREAM PATCH SUMMARY
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Patch: wifi: mac80211: validate extension-frame layout before RX
Commit: 625fc704b19cb48d7d269ad54ffffb4d3bf9c7ed
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=625fc704b19cb48d7d269ad54ffffb4d3bf9c7ed

Commit description:

Extension frames only have the extension header at the regular 802.11
header offset. The generic RX path can still reach helpers and interface
dispatch code that read regular header address fields before unsupported
extension subtypes are dropped.

mac80211 currently only handles S1G beacon extension frames. Drop other
extension subtypes before they can reach regular-header RX processing.
For S1G beacons, linearize the SKB with the management-frame path and
require the fixed S1G beacon header, including optional fixed fields
indicated by frame control, before generic RX dispatch.

Route S1G beacons through the station/default-link RX path without
regular-header station lookup. Avoid regular-header address reads in the
mac80211 RX paths that process S1G extension beacons, including
accept-frame, duplicate-detection, address-copy, and MLO
address-translation paths.

Also make ieee80211_get_bssid() length-safe before returning the S1G
source-address pointer.

Fixes: 09a740c ("mac80211: receive and process S1G beacons")
Cc: stable@vger.kernel.org
Signed-off-by: Zhao Li <enderaoelyther@gmail.com>
Link: https://patch.msgid.link/20260611161943.91069-5-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/rx.c
  net/mac80211/util.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=625fc704b19cb48d7d269ad54ffffb4d3bf9c7ed

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

The original Linux kernel CVE announcement for CVE-2026-68470 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68470

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:N/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS vector: AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H
  The Best / paranoid CVSS score: 7.6

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: 5
  Paranoid ActionableScore: 6

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: YES
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).