[CVE-2026-74410][MODERATE 7.0] wifi: rtw88: fix OOB read from firmware RX descriptor exceeding DMA buffer [ Upstream

[CVE-2026-74410][MODERATE 7.0] wifi: rtw88: fix OOB read from firmware RX descriptor exceeding DMA buffer [ Upstream

[AL-KERNEL]

CVE: CVE-2026-74410
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: wifi: rtw88: fix OOB read from firmware RX descriptor exceeding DMA buffer [ Upstream
Commit: 913bd7d3d3d842b5c1d2b908a0201efa8fc79793
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=913bd7d3d3d842b5c1d2b908a0201efa8fc79793
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74410
Analysis date: Sun, 16 Aug 2026 03:14:46 -0400
ActionableScore: 5
ActionableScore lower bound: 4
Actionable bucket: Actionable Moderate at minimum
Manual review required: YES

Summary:
An OOB read in the rtw88 PCIe Wi-Fi RX path can occur when firmware-controlled descriptor length fields make `skb_put_data()` copy beyond the DMA RX buffer, allowing an adjacent Wi-Fi attacker under suitable firmware conditions to cause a kernel crash and potentially limited memory disclosure.

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ABOUT THIS REPORT
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The original Linux kernel CVE announcement for CVE-2026-74410 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74410

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-2026-74410	MODERATE	CHECK WITH IMPACT FROM ORIG NN IMPORTANT	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:N/A:H';CWE-125;*CWE-20;*CWE-787;Other CVSS 'AV:A/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:H';BEST CVSS score: '6.8';DESCR 'An OOB read in the rtw88 PCIe RX path can occur because rtw_pci_rx_napi() computes new_len from pkt_len plus pkt_offset without checking it against RTK_PCI_RX_BUF_SIZE. These fields come from the firmware RX descriptor and can make skb_put_data copy more bytes than the pre allocated DMA RX buffer contains. For the CVSS the PR:N is used because a plausible external trigger does not require local privileges on the target system. The attack surface is adjacent network Wi-Fi rather than general Internet reachability, so AV:A is used. Impact is at least denial of service via kernel crash or fault and may include confidentiality impact from reading beyond the RX buffer. No direct OOB write or privilege escalation primitive is shown by the patch context.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Actionable Moderate at minimum (with actual score 5)	YES	REMOTE READ OOB SIMPLEFIX NETWORK DMAorINTERRUPT LINUS PACKET  DECREASED_TO_MODERATE70_BASED_ON_ACTIONABLESCORELOWERTHAN6 DECREASED_TO_MODERATEREG_BASED_ON_FALSEPOSCHECKOFKP	NO	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

Conservative signals:

* +1 Firmware-mediated external influence. The oversized length comes from firmware RX descriptor fields, and the practical external influence is likely through Wi-Fi RX traffic processed by device firmware rather than a direct Internet-reachable parser.
* +1 Reliable kernel crash / strong DoS concern. The PCIe path can make `skb_put_data()` copy beyond the pre-allocated DMA RX buffer, which is a concrete OOB read in kernel context and can plausibly crash or fault.
* +1 Confidentiality impact plausible. The copied bytes may include memory beyond the RX buffer and can become part of an skb, so limited kernel memory disclosure is technically plausible, although the external read-back path is not proven.
* +1 Privileged kernel/device-management memory corruption path. The bug is in a wireless driver RX path involving firmware-fed descriptor metadata and DMA-adjacent buffers.

Paranoid additional signal:

* +1 Broad deployed driver exposure. Realtek rtw88 PCIe Wi-Fi devices are common enough that an adjacent-network RX-path OOB read should not be auto-closed without review.

Not awarded:

* No +2 remote reachable. This is better modeled as adjacent Wi-Fi / firmware-mediated influence, not general AV:N Internet reachability.
* No +2 strong memory corruption primitive. The patch shows OOB read, not OOB write, UAF, double free, type confusion, arbitrary write, or attacker-controlled object replacement.
* No privilege escalation signal. There is no demonstrated write primitive, reclaim primitive, callback control, refcount takeover, or object confusion.

## 3. Reachability analysis

A plausible attacker would need to be within Wi-Fi range or otherwise able to influence frames received by the affected Realtek rtw88 PCIe device. No local account on the victim is required for the adjacent-network model, but the descriptor fields are firmware-controlled, so exploitability depends on whether external traffic can reliably drive firmware to emit oversized `pkt_len + pkt_offset` values. Namespaces and containers do not materially affect reachability because the vulnerable path is below normal local namespace boundaries in the hardware RX driver path. The affected path is only present on systems using the rtw88 PCIe driver and affected hardware, but this is not an exotic debug-only configuration.

Call-site confidence: high. The relevant call site is visible: `new_len` is computed and then used to allocate an skb and copy data from the DMA RX buffer.

## 4. Severity interpretation

This is more than an ordinary Moderate correctness issue because it is an adjacent-network reachable OOB read in a kernel wireless RX path. It is not a strong Important candidate by default because the primitive is read-only and there is no supported path to arbitrary write, UAF-based reclaim, or privilege escalation. The realistic impact is DoS plus possible limited confidentiality exposure. The paranoid score keeps it in Actionable Moderate range because wireless RX parsing bugs with firmware-fed DMA descriptors can be underestimated and should receive manual review.

## 5. One-sentence report phrase

An OOB read in the rtw88 PCIe Wi-Fi RX path can occur when firmware-controlled descriptor length fields make `skb_put_data()` copy beyond the DMA RX buffer, allowing an adjacent Wi-Fi attacker under suitable firmware conditions to cause a kernel crash and potentially limited memory disclosure.

## 6. Manual review recommendation

MANUAL CHECK REQUIRED

Reason: adjacent-network reachable OOB read in a wireless driver with possible confidentiality impact, but exploitability depends on firmware behavior and whether copied OOB bytes can be observed or weaponized.

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

Patch: wifi: rtw88: fix OOB read from firmware RX descriptor exceeding DMA buffer [ Upstream
Commit: 913bd7d3d3d842b5c1d2b908a0201efa8fc79793
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=913bd7d3d3d842b5c1d2b908a0201efa8fc79793

Changed files:
  drivers/net/wireless/realtek/rtw88/pci.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=913bd7d3d3d842b5c1d2b908a0201efa8fc79793

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

The original Linux kernel CVE announcement for CVE-2026-74410 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74410

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:N/A:H
  The Best / paranoid CVSS vector: AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:H
  The Best / paranoid CVSS score: 6.8

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: 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).