[CVE-2026-68355][MODERATE 7.0] wifi: ath11k: fix potential buffer underflow in ath11k_hal_rx_msdu_list_get() [ Upstream

[CVE-2026-68355][MODERATE 7.0] wifi: ath11k: fix potential buffer underflow in ath11k_hal_rx_msdu_list_get() [ Upstream

[AL-KERNEL]

CVE: CVE-2026-68355
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: wifi: ath11k: fix potential buffer underflow in ath11k_hal_rx_msdu_list_get() [ Upstream
Commit: 69a6a4f60b2da92c0bdfd9264b8ffe053f51f52a
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=69a6a4f60b2da92c0bdfd9264b8ffe053f51f52a
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68355
Analysis date: Mon, 10 Aug 2026 17:48:01 -0400
ActionableScore: 5
ActionableScore lower bound: 3
Actionable bucket: Strong Important candidate / Actionable Moderate at minimum
Manual review required: YES

Summary:
A buffer underflow in ath11k_hal_rx_msdu_list_get() can access msdu_details(i - 1) when the first MSDU descriptor has a zero buffer address, potentially allowing an adjacent Wi-Fi attacker through firmware mediated RX descriptor state to trigger a kernel crash or other driver memory corruption.

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

The original Linux kernel CVE announcement for CVE-2026-68355 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68355

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.

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

CVE-2026-68355	MODERATE	CHECK WITH IMPACT FROM ORIG NN LOW	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-124;*CWE-787;*CWE-20;Other CVSS 'AV:A/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H';BEST CVSS score: '7.5';DESCR 'An underflow in ath11k_hal_rx_msdu_list_get() can access msdu_details(i - 1) when i is 0 and the first MSDU descriptor has a zero buffer address. Because this RX parsing path handles descriptors associated with received Wi-Fi traffic, a nearby attacker may be able to influence the vulnerable path indirectly through crafted or malformed 802.11 traffic, although reliable control of the descriptor state is not proven from the patch alone. For the CVSS the PR:N is used for the paranoid score because no local account is needed if the condition is reachable from adjacent Wi-Fi input. The attack vector is adjacent network rather than Internet reachable. Impact is at least denial of service, and because the bug is a buffer underflow in kernel driver memory, worst case impact may include confidentiality or integrity compromise and should be reviewed manually.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Strong Important candidate / Actionable Moderate at minimum (with actual score 4)	YES	REMOTE KASAN OOB SIMPLEFIX NETWORK HARDWARE  INCREASED_TO_HIGH_BASED_ON_GUESSCVSS DECREASED_TO_MODERATE70_BASED_ON_ACTIONABLESCORELOWERTHAN7 DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN5	NO	NO	checked

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

ActionableScore=5
ActionableScoreLower=3

## 1. ActionableScore

* Conservative score: 3
* Paranoid score: 5
* Final recommended bucket: **Strong Important candidate / Actionable Moderate at minimum**::

## 2. Signal breakdown

Conservative signals:

* Firmware-mediated external influence: +1. The bad MSDU descriptor state is consumed in the ath11k Wi-Fi RX path and may be influenced indirectly through firmware or hardware RX descriptor processing.
* Memory corruption, weak or indirect corruption candidate: +1. The code can access `msdu_details[i - 1]` when `i == 0`, which is an out-of-bounds access before the descriptor array.
* Privileged kernel or device-management memory corruption path: +1. The bug is in a trusted wireless driver RX descriptor parsing path involving hardware or firmware supplied metadata.
* Availability impact realistic: +1. An out-of-bounds descriptor access in kernel RX processing can plausibly crash the driver or kernel.
* Hard or unreliable trigger: -1. The patch does not prove that an attacker can reliably force the first descriptor to have a zero buffer address.
* No attacker-controlled payload or overwrite target shown: -1. The patch shows an underflow access, but not an arbitrary write, controlled overwrite, reclaim primitive, or controlled object replacement.

Paranoid additional interpretation:

* Weak LPE concern: +1. Because this is a kernel buffer underflow in a Wi-Fi RX path, adjacent memory may be interpreted as descriptor state, but no strong exploitation primitive is demonstrated.

## 3. Reachability analysis

The likely attacker model is adjacent wireless exposure, not Internet-routable remote reachability. A nearby attacker may be able to influence RX processing through crafted or malformed 802.11 traffic, but the actual zero-buffer descriptor condition appears firmware or hardware mediated and is not proven to be directly controllable from the patch alone.

No local account is required if the descriptor condition is reachable from Wi-Fi input, so the practical PR interpretation is close to PR:N for the paranoid case. The issue only affects systems using ath11k-supported Qualcomm Wi-Fi hardware and the relevant RX path, so exposure is hardware dependent but not merely a debug or rare kernel configuration.

Call-site confidence: medium. The affected function and RX descriptor context are visible, but the full downstream use of `msdu_desc_info` is not included in the provided patch.

## 4. Severity interpretation

This is more than an ordinary Moderate correctness fix because it is an out-of-bounds access in kernel driver RX parsing with possible adjacent-network influence. However, it is not a proven Important-class LPE because the patch does not show attacker-controlled overwrite, UAF reclaim, callback control, type confusion, arbitrary write, or information disclosure.

Conservatively this is a borderline issue requiring review. Paranoid triage places it at Actionable Moderate because kernel memory underflow in a Wi-Fi RX path can historically hide higher impact than the minimal static-analysis description suggests.

## 5. One-sentence report phrase

A buffer underflow in ath11k_hal_rx_msdu_list_get() can access msdu_details(i - 1) when the first MSDU descriptor has a zero buffer address, potentially allowing an adjacent Wi-Fi attacker through firmware mediated RX descriptor state to trigger a kernel crash or other driver memory corruption.

## 6. Manual review recommendation

MANUAL CHECK REQUIRED

Reason: this is a kernel buffer underflow in a Wi-Fi RX descriptor parsing path with possible adjacent-network influence. The practical exploitability is not proven, but the bug class and exposure are strong enough that it should not be auto-closed.

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

Patch: wifi: ath11k: fix potential buffer underflow in ath11k_hal_rx_msdu_list_get() [ Upstream
Commit: 69a6a4f60b2da92c0bdfd9264b8ffe053f51f52a
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=69a6a4f60b2da92c0bdfd9264b8ffe053f51f52a

Changed files:
  drivers/net/wireless/ath/ath11k/dp_rx.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=69a6a4f60b2da92c0bdfd9264b8ffe053f51f52a

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

The original Linux kernel CVE announcement for CVE-2026-68355 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68355

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: 3
  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: NO
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).