[CVE-2026-93784][MODERATE REGULAR] wifi: cfg80211: validate IEs in cfg80211_wext_siwgenie() [ Upstream

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

CVE: CVE-2026-93784
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: wifi: cfg80211: validate IEs in cfg80211_wext_siwgenie() [ Upstream
Commit: c970879e03b23a27df42caf7ba506485a165fb96
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=c970879e03b23a27df42caf7ba506485a165fb96
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-93784
Analysis date: Thu, 24 Sep 2026 19:34:56 -0400
ActionableScore: 1
ActionableScore lower bound: 0
Actionable bucket: Ordinary Moderate
Manual review required: NO

Summary:
No one-sentence report phrase was found.

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

The original Linux kernel CVE announcement for CVE-2026-93784 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-93784

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: NO

A detailed explanation of the methodology and priority rules is included
at the end of this message.

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

CVE-2026-93784	MODERATE	https://www.kernelcve.org/list/?q=CVE-2026-93784 CHECK WITH IMPACT FROM ORIG NN IMPORTANT	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:H';CWE-125;CWE-191;*CWE-20;Other CVSS 'AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '6.6';DESCR 'A malformed information element buffer supplied through the legacy SIOCSIWGENIE wireless ioctl can be stored and later parsed during a connection attempt without structural validation. A truncated one byte information element causes skip_ie to read the missing length byte out of bounds. A malformed split result can also make an unsigned length subtraction wrap before memcpy, which is reported to cause a FORTIFY panic and kernel DoS. For the CVSS the PR:L paranoid rating assumes the caller has delegated network administration capability or equivalent control of a wireless interface, rather than full host administration. The issue is locally reachable through a wireless control ioctl and is not directly network reachable from an unauthenticated remote station. The confirmed impact is local DoS. The out of bounds parser access and wrapped memcpy length warrant manual review for impact on builds or configurations where the FORTIFY check does not safely stop execution.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 1)	YES	REMOTE KASAN OOB SIMPLEFIX KERNEL_PANIC_PLUS_UAF SYZBOT  DECREASED_TO_MODERATE70_BASED_ON_ACTIONABLESCORELOWERTHAN5 DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN4	NO	NO	checked

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

ActionableScore=1
ActionableScoreLower=0
PrimitiveClass=CLASS_B
RealUAF=NO
HostAdminRequired=YES
NamespaceScopedPrivilege=NO
ImportantCandidate=NO
ManualReview=RECOMMENDED
AutoDowngradeAllowed=YES

1. ActionableScore

* Raw conservative score: 2
* Conservative score: 0
* Raw paranoid score: 3
* Paranoid score: 1
* Final recommended bucket: **Ordinary Moderate**::

Conservative arithmetic: +1 weak invalid memory-access primitive, +1 reliable kernel DoS, -2 host-admin-equivalent CAP_NET_ADMIN requirement. No floor applies.

Paranoid arithmetic: the same signals, plus +1 for the concrete wrapped memcpy length reaching a potentially unsafe copy operation if FORTIFY protection is absent or ineffective, then -2 for the privilege requirement.

2. Signal breakdown

Positive signals:

* +1 Weak corruption candidate. A malformed IE is retained and later causes an out-of-bounds read in skip_ie() and an unsigned length underflow before memcpy. This is one parser and length-validation defect, not separate stacked corruption bonuses.
* +1 Reliable kernel crash or strong DoS. The supplied trace describes a FORTIFY panic after the wrapped memcpy length reaches the protected copy path.
* +1 Paranoid only. The computed size can wrap to SIZE_MAX before memcpy. On builds where the relevant FORTIFY checking is disabled, unavailable, or not effective for this call, this creates a constrained unsafe-copy concern. No controlled overwrite is demonstrated.

Negative signals:

* -2 Host-admin-equivalent privilege requirement. SIOCSIWGENIE and SIOCSIWESSID are legacy Wireless Extensions set ioctls. Their set operations are protected by CAP_NET_ADMIN through the WEXT permission path. This is a concrete prerequisite for the supplied trigger sequence.

Important non-awarded signals:

* Controlled reclaim is not demonstrated.
* Arbitrary or directed kernel write is not demonstrated.
* No UAF, stale object, double free, refcount mutation, or lifetime violation is established.
* No confidentiality impact is awarded because the out-of-bounds read is not shown to be copied back to userspace, a device, or the network.
* No integrity impact is awarded because the observed protected path panics before an uncontrolled copy is demonstrated.
* Remote reachability is not established. The malformed buffer enters through local SIOCSIWGENIE control-plane input, not over-the-air management frames.
* Local unprivileged trigger is not awarded because the complete ioctl sequence requires CAP_NET_ADMIN.
* No additional Availability point is awarded because the same FORTIFY panic is already counted as the kernel DoS consequence.

3. Reachability analysis

The evaluated attacker is a local process able to issue Wireless Extensions control ioctls on the affected wireless interface. The supplied sequence requires SIOCSIWGENIE to install the malformed IE buffer and SIOCSIWESSID to initiate the later connection processing path.

Legacy WEXT set operations are protected by CAP_NET_ADMIN. This is treated as host-admin-equivalent access for this triage because the permission check is based on the legacy WEXT capability path rather than a demonstrated attacker-obtainable namespace-scoped capability.

NamespaceScopedPrivilege is NO. The supplied material does not establish a complete trigger path through an attacker-created network namespace and a namespace-owned wireless device. In particular, ordinary container networking or a veth device does not establish control of a physical cfg80211 wireless interface through this legacy WEXT sequence.

No special or rare hardware is required beyond a usable affected wireless interface. However, the privilege-gated local control-plane prerequisite materially limits practical attacker reachability. This is not a race condition and no timing penalty is applied.

4. Primitive and severity interpretation

The exact primitive is malformed Information Element parsing. A one-byte IE can cause skip_ie() to read a missing length byte beyond the allocated IE buffer. A malformed split result can also return an offset greater than the buffer length, causing unsigned subtraction to wrap before memcpy.

This is neither a UAF nor a lifetime issue. There is no active structured stale-object reuse, no post-free operation, and no repeated release or refcount mutation.

The supplied evidence establishes a kernel panic through the FORTIFY-protected copy path. The patch does not establish attacker-controlled destination selection, payload placement after the bounds failure, arbitrary write, controlled heap replacement, disclosure, privilege escalation, or a security-boundary bypass.

The primitive is classified as CLASS_B because the malformed parser state reaches an out-of-bounds read and a wrapped memcpy length. Nevertheless, it is constrained: the demonstrated outcome is a protected kernel panic, and the attacker must already hold CAP_NET_ADMIN. ImportantCandidate is therefore NO. AutoDowngradeAllowed is YES because no unresolved controlled corruption, active lifetime primitive, authorization bypass, or post-free mutation is established.

Operationally, this is primarily a privileged local kernel DoS. It should be checked where kernels may be built without effective FORTIFY coverage, but the supplied patch alone does not support Important-class exploitation.

5. One-sentence report phrase

A local attacker with CAP_NET_ADMIN can provide malformed Wireless Extensions IE data through SIOCSIWGENIE and trigger an out-of-bounds parser read and a FORTIFY kernel panic during a later connection attempt, resulting in denial of service.

6. Manual review recommendation

MANUAL CHECK RECOMMENDED

Confirm whether the affected product enables effective CONFIG_FORTIFY_SOURCE protection for this memcpy path and whether any supported deployment delegates CAP_NET_ADMIN over a usable physical wireless interface to less-trusted local users or services.

7. Call-site confidence

Call-site confidence: medium

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

Patch: wifi: cfg80211: validate IEs in cfg80211_wext_siwgenie() [ Upstream
Commit: c970879e03b23a27df42caf7ba506485a165fb96
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=c970879e03b23a27df42caf7ba506485a165fb96

Changed files:
  net/wireless/wext-sme.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=c970879e03b23a27df42caf7ba506485a165fb96

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

The original Linux kernel CVE announcement for CVE-2026-93784 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-93784

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:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS vector: AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:H
  The Best / paranoid CVSS score: 6.6

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: 0
  Paranoid ActionableScore: 1

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).