[CVE-2026-72065][MODERATE 7.0] net: mana: Validate the packet length reported by the NIC [ Upstream

[CVE-2026-72065][MODERATE 7.0] net: mana: Validate the packet length reported by the NIC [ Upstream

[AL-KERNEL]

CVE: CVE-2026-72065
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: YES
Patch: net: mana: Validate the packet length reported by the NIC [ Upstream
Commit: 2e276b14b6d378372bf0152df89286cbe7632fb0
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=2e276b14b6d378372bf0152df89286cbe7632fb0
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72065
Analysis date: Sat, 15 Aug 2026 10:51:10 -0400
ActionableScore: 7
ActionableScore lower bound: 5
Actionable bucket: Strong Important candidate / Actionable Moderate at minimum
Manual review required: YES

Summary:
The MANA RX path trusted NIC reported packet lengths before skb processing, so a malicious or faulty device could report an oversized packet length and cause kernel memory boundary misuse, with practical DoS impact and possible OOB access requiring manual review.

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

The original Linux kernel CVE announcement for CVE-2026-72065 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72065

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-2026-72065	MODERATE	CHECK WITH IMPACT FROM ORIG NN LOW	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H';*CWE-20;CWE-125;*CWE-787;CWE-119;Other CVSS 'AV:A/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:H';BEST CVSS score: '8.8';DESCR 'The MANA RX path trusted the packet length reported in the NIC completion queue entry before passing it into skb processing. If the device reports a length larger than the RX buffer size, skb handling may operate beyond the valid receive buffer and can crash the kernel. For the CVSS the PR:N value is used because no privileges on the victim are required when the attacker can influence the RX input or the virtual NIC completion metadata. The issue is best treated as adjacent or device mediated rather than a generic Internet reachable service bug. Impact is at least denial of service via kernel crash. In the paranoid case it may also allow confidentiality or integrity impact because the bug is a length validation failure at a kernel memory boundary in the RX path.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Strong Important candidate / Actionable Moderate at minimum (with actual score 7)	YES	REMOTE OOB NETWORK SKB HARDWARE KPANIC PACKET  KPANIC INCREASED_TO_HIGH_BASED_ON_GUESSCVSS DECREASED_TO_MODERATE7_BASED_ON_FALSEPOSCHECKOFKP	NO	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:

* +1 Firmware-mediated external influence: the RX CQE is supplied by the NIC or virtual NIC and is explicitly described as untrusted.
* +1 Memory corruption, weak/indirect corruption candidate: unchecked pktlen is passed into skb processing and may exceed the real RX buffer size.
* +1 Privileged kernel/device-management memory corruption path: the bug is in a trusted network driver RX path using NIC supplied metadata.
* +1 Reliable kernel crash / strong DoS: oversized length in skb construction can plausibly crash the kernel.
* +1 Broad/default/common exposure within affected environment: MANA is a normal Azure network adapter path when this driver is used.

Paranoid additional signals:

* +1 Confidentiality impact plausible: an oversized skb length may cause reads beyond the valid RX buffer in later packet processing.
* +1 Integrity impact plausible: length confusion at a kernel memory boundary in RX skb handling is a plausible corruption sink, although not demonstrated as an arbitrary write.

Not counted:

* No +2 generic remote reachability: this is not a generic Internet protocol parser bug.
* No strong LPE bonus: no attacker-controlled reclaim, callback control, arbitrary write, or demonstrated privilege escalation primitive is shown.
* No Dirty-Pipe-like ownership/COW signal.

## 3. Reachability analysis

The most realistic trigger is a malicious, compromised, buggy, or externally influenced NIC or virtual NIC that reports an RX packet length larger than the allocated RX buffer. A remote network sender may influence packet contents and traffic shape, but the critical untrusted value is the NIC completion metadata, so firmware-mediated or device-mediated exposure is more defensible than plain AV:N-style remote exposure.

No local privileges on the guest are required if the attacker can influence the NIC or virtual NIC input path. Namespaces and containers do not materially change the trigger model because the vulnerable path is below ordinary namespace isolation in the host or guest kernel network driver. The issue is default-reachable only on systems using the Microsoft Azure MANA driver.

Call-site confidence: high. The patch shows the bad value being checked immediately before mana_refill_rx_oob() and mana_rx_skb(), so the relevant skb-processing call path is visible.

## 4. Severity interpretation

This should not be auto-closed as an ordinary Moderate. Realistically, it is an Actionable Moderate because the direct evidence supports a device-mediated oversized-length bug in a kernel RX path with strong DoS potential. Paranoid handling can treat it as a Strong Important candidate because the bug is a missing bounds check at a kernel memory boundary, and the downstream skb path may create confidentiality or integrity risk even though no concrete arbitrary write or LPE primitive is demonstrated.

## 5. One-sentence report phrase

The MANA RX path trusted NIC reported packet lengths before skb processing, so a malicious or faulty device could report an oversized packet length and cause kernel memory boundary misuse, with practical DoS impact and possible OOB access requiring manual review.

## 6. Manual review recommendation

MANUAL CHECK REQUIRED. YES REQUIRES MANUAL CHECK.

Reason: this is a network driver RX memory-boundary validation bug fed by NIC completion metadata, and the patch prevents an oversized length from reaching skb processing.

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

Patch: net: mana: Validate the packet length reported by the NIC [ Upstream
Commit: 2e276b14b6d378372bf0152df89286cbe7632fb0
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=2e276b14b6d378372bf0152df89286cbe7632fb0

Changed files:
  drivers/net/ethernet/microsoft/mana/mana_en.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=2e276b14b6d378372bf0152df89286cbe7632fb0

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

The original Linux kernel CVE announcement for CVE-2026-72065 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72065

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:L/PR:N/UI:N/S:U/C:H/I:H/A:H
  The Best / paranoid CVSS score: 8.8

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: 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: MODERATE
KPANIC detected for this report: YES
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).