[CVE-2026-64030][IMPORTANT] wifi: mac80211: bounds-check link_id in ieee80211_ml_epcs [ Upstream

[CVE-2026-64030][IMPORTANT] wifi: mac80211: bounds-check link_id in ieee80211_ml_epcs [ Upstream

[AL-KERNEL]

CVE: CVE-2026-64030
Priority: IMPORTANT
AL-KERNEL base severity: IMPORTANT
KPANIC flag: YES
Patch: wifi: mac80211: bounds-check link_id in ieee80211_ml_epcs [ Upstream
Commit: 2d8379834800c30602f24c71ab7c40f5fe84d200
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=2d8379834800c30602f24c71ab7c40f5fe84d200
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-64030
Analysis date: Sun, 19 Jul 2026 20:35:53 -0400
ActionableScore: 7
ActionableScore lower bound: 5
Actionable bucket: Strong Important candidate / Actionable Moderate at minimum
Manual review required: YES

Summary:
A connected WiFi 7 AP can send an EPCS response with `link_id = 15`, causing mac80211 to read past `sdata->link[]`, interpret adjacent data as a link pointer, and crash the kernel, with limited type-confusion concern requiring manual review.

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

The original Linux kernel CVE announcement for CVE-2026-64030 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-64030

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.

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

CVE-2026-64030	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-129;CWE-125;**CWE-476;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 bounds check bug in mac80211 EPCS handling allows a connected WiFi 7 AP to supply link_id 15 in a PER_STA_PROFILE subelement even though sdata link has valid indices 0 to 14. The out of bounds entry is read as a pointer and can bypass the NULL check because it overlaps initialized activate_links_work data, then ieee80211_sta_wmm_params dereferences the bogus link pointer and crashes the kernel. For the CVSS the PR:N is used for the paranoid score because the attacker does not need privileges on the victim once it can act as the associated AP or control the adjacent WiFi link. The issue is adjacent network reachable rather than Internet reachable. Impact is at least denial of service via kernel crash and worst case may allow limited confidentiality or integrity impact due to type confusion from an out of bounds pointer read, so it should be reviewed manually.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Strong Important candidate / Actionable Moderate at minimum (with actual score 7)	YES	REMOTE OOB DANGER KERNEL_PANIC_PLUS_UAF KPANIC 	YES	NO	checked

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

ActionableScore=7
ActionableScoreLower=5

## 1. ActionableScore

* Conservative score: 5
* Paranoid score: 7
* Final recommended bucket: **Strong Important candidate / Actionable Moderate at minimum**::

## 2. Signal breakdown

Conservative signals:

* Remote reachable / network-triggerable: +2
  Trigger is an 802.11 action frame from a connected WiFi 7 AP. This is adjacent-network reachable, not Internet reachable, but still network-triggerable.
* Memory corruption, weak/indirect corruption candidate: +1
  `link_id = 15` causes an out-of-bounds array read from `sdata->link[]`, interpreted as a pointer.
* Reliable kernel crash / strong DoS: +1
  The bogus pointer is passed to `ieee80211_sta_wmm_params()` and dereferenced via `link->sdata`, causing kernel crash.
* Broad/default/common subsystem exposure: +1
  mac80211 is a common Linux WiFi client subsystem, although the exact trigger requires WiFi 7 MLO/EPCS conditions.

Paranoid additional signals:

* Weak LPE concern: +1
  The bug is more than a simple NULL dereference because an out-of-bounds word is interpreted as a kernel object pointer and then dereferenced as a different structure. No reliable write or reclaim primitive is shown.
* Confidentiality impact plausible: +1
  Limited C impact is plausible only under paranoid interpretation due to invalid object interpretation, not because an info leak is demonstrated.
* Integrity impact plausible: +1
  Limited I impact is plausible only under paranoid interpretation because type confusion-like pointer use can sometimes become a corruption sink.
* Corruption primitive highly constrained / no attacker-controlled payload: -1
  The patch shows controlled index selection but not attacker-controlled pointer contents, arbitrary write, callback control, or reclaim.

## 3. Reachability analysis

A connected or malicious WiFi 7 AP can trigger the bug by sending an EPCS Enable Response action frame with a `PER_STA_PROFILE` subelement where `link_id = 15`. The victim does not need local privileges, so PR is effectively none for the adjacent-network attacker model. This is not Internet-reachable and requires the attacker to control or impersonate the associated AP, or otherwise operate in the adjacent WiFi environment. Containers and namespaces are not the relevant privilege boundary here because the trigger is in the wireless client receive/control path.

## 4. Severity interpretation

This is not an ordinary local Moderate issue because the trigger is adjacent-network reachable and produces a reliable kernel crash. The demonstrated impact is DoS. The theoretical memory-corruption potential is limited but non-zero because the bug performs an out-of-bounds pointer read and then treats adjacent kernel data as a `link` object. There is no demonstrated arbitrary write, controlled object replacement, UAF reclaim, or callback hijack, so the conservative score should not be pushed into Critical-like territory. Paranoid handling as Strong Important candidate is justified for manual review because the bug combines network adjacency, OOB pointer use, and kernel crash in a common wireless subsystem.

## 5. One-sentence report phrase

A connected WiFi 7 AP can send an EPCS response with `link_id = 15`, causing mac80211 to read past `sdata->link[]`, interpret adjacent data as a link pointer, and crash the kernel, with limited type-confusion concern requiring manual review.

## 6. Manual review recommendation

MANUAL CHECK REQUIRED

Reason: adjacent-network trigger plus out-of-bounds pointer interpretation and reliable kernel crash should not be auto-closed, even though practical privilege escalation is not demonstrated.

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

Patch: wifi: mac80211: bounds-check link_id in ieee80211_ml_epcs [ Upstream
Commit: 2d8379834800c30602f24c71ab7c40f5fe84d200
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=2d8379834800c30602f24c71ab7c40f5fe84d200

Changed files:
  net/mac80211/mlme.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=2d8379834800c30602f24c71ab7c40f5fe84d200

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

The original Linux kernel CVE announcement for CVE-2026-64030 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-64030

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: 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: 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).