[CVE-2026-53230][MODERATE 7.0] net/mlx5: Fix slab-out-of-bounds in mlx5_query_nic_vport_mac_list [ Upstream

[CVE-2026-53230][MODERATE 7.0] net/mlx5: Fix slab-out-of-bounds in mlx5_query_nic_vport_mac_list [ Upstream

[AL-KERNEL]

CVE: CVE-2026-53230
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: YES
Patch: net/mlx5: Fix slab-out-of-bounds in mlx5_query_nic_vport_mac_list [ Upstream
Commit: 41781f2789309462520a93822e946521ed78f97f
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=41781f2789309462520a93822e946521ed78f97f
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53230
Analysis date: Thu, 25 Jun 2026 17:53:52 -0400
ActionableScore: 7
ActionableScore lower bound: 4
Actionable bucket: Strong Important candidate / Actionable Moderate at minimum
Manual review required: YES

Summary:
No one-sentence report phrase was found.

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

The original Linux kernel CVE announcement for CVE-2026-53230 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53230

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-2026-53230	MODERATE	CHECK	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:A/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H';*CWE-787;CWE-125;CWE-131;Other CVSS 'AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:H';BEST CVSS score: '7.1';DESCR 'mlx5_query_nic_vport_mac_list can size the firmware command output buffer from PF capabilities while a VF vport can have a larger configured MAC list limit. When the host queries such a VF vport, the firmware response can exceed the allocated buffer and trigger a slab out of bounds access in the mlx5 eswitch workqueue. For the CVSS the PR:L is used for the paranoid score because an attacker may only need control of a VF tenant or delegated network administration path after the host enables the affected VF configuration. The issue is not directly reachable through ordinary Internet packet traffic. It is mainly relevant to hosts using mlx5 SR-IOV or eswitch VF management. Impact is at least denial of service via kernel crash and the buffer overflow context makes limited or full confidentiality and integrity impact plausible enough for manual review.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Strong Important candidate / Actionable Moderate at minimum (with actual score 6)  SKIP CVE-2026-53230  SKIP No affected files built, so skip this CVE NO  - - unknown 	MAYBE	REMOTE READ KASAN OOB NOMEMCHK NETWORK LOG HARDWARE KPANIC 	-	-	checked

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

1. ActionableScore

ActionableScore=7
ActionableScoreLower=4

* Conservative score: 4
* Paranoid score: 7
* Final recommended bucket: **Strong Important candidate / Actionable Moderate at minimum**

2. Signal breakdown

* Firmware-mediated external influence: +1. The malformed size relationship comes from firmware-reported VF vport capabilities and firmware command output.
* Local or delegated VF tenant trigger in paranoid model: +1. A VF tenant or delegated network-management path may influence VF vport state after the host enables the affected SR-IOV configuration.
* Generic memory corruption candidate: +2. The old code sizes buffers from PF limits but iterates using VF-reported allowed_list_size, creating slab out-of-bounds access and likely OOB copy into the caller MAC list.
* Weak LPE concern: +1. The primitive is not clearly an arbitrary write, but heap OOB access in a privileged driver workqueue is enough for manual privilege-escalation review.
* Reliable kernel crash / strong DoS: +1. KASAN shows a reproducible slab-out-of-bounds in mlx5 eswitch workqueue.
* Privileged kernel/device-management memory corruption path: +1. The corruption occurs in mlx5 eswitch / vport management code driven by device and firmware state.
* Confidentiality impact plausible: +1. OOB read is present, though no direct user-visible leak is demonstrated.
* Integrity impact plausible: +1. OOB write into the allocated MAC list path is plausible, but target and payload control appear constrained.
* Constrained primitive / limited target control: -1. The copied data is MAC-list data and the overwrite target is adjacent allocation-dependent, not a demonstrated arbitrary write.
* Rare and configuration-dependent exposure: -1. Requires mlx5 hardware, SR-IOV/eswitch/VF vport management, and mismatched PF/VF MAC-list limits.

3. Reachability analysis

This is not ordinary remote network packet reachability. The realistic path is firmware-mediated and device-management mediated on hosts using Mellanox mlx5 SR-IOV or eswitch VF management. Conservative triggering likely requires administrator-created VF configuration, for example via devlink. The paranoid model treats reduced-privilege VF tenant control or delegated network-management control as PR:L-like because the attacker may not be full host root but may still influence VF vport state. Containers or namespaces matter only if they expose VF or delegated netdev control to less privileged workloads.

4. Severity interpretation

This is stronger than an ordinary Moderate because the patch fixes a slab out-of-bounds condition in a privileged network driver workqueue. Realistic exploitation is limited by hardware and configuration requirements, and the primitive is constrained rather than a demonstrated arbitrary write. Still, the combination of firmware-fed sizing mismatch, heap OOB access, VF management exposure, and possible delegated tenant influence makes it an Actionable Moderate at minimum and a Strong Important candidate under the paranoid interpretation.

5. One-sentence report phrase

A firmware-mediated mlx5 VF vport MAC-list size mismatch can cause slab out-of-bounds access in mlx5_query_nic_vport_mac_list, leading to kernel crash and possible constrained memory corruption on SR-IOV or eswitch hosts.

6. Manual review recommendation

MANUAL CHECK REQUIRED

Manual review is required because this is a firmware/device-management slab out-of-bounds issue with plausible OOB write behavior in a privileged kernel driver path, even though practical exposure is limited to specific mlx5 SR-IOV/eswitch configurations.

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

Patch: net/mlx5: Fix slab-out-of-bounds in mlx5_query_nic_vport_mac_list [ Upstream
Commit: 41781f2789309462520a93822e946521ed78f97f
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=41781f2789309462520a93822e946521ed78f97f

Changed files:
  drivers/net/ethernet/mellanox/mlx5/core/eswitch.c
  drivers/net/ethernet/mellanox/mlx5/core/vport.c
  include/linux/mlx5/vport.h

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=41781f2789309462520a93822e946521ed78f97f

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

The original Linux kernel CVE announcement for CVE-2026-53230 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53230

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:H/PR:L/UI:N/S:U/C:L/I:L/A:H
  The Best / paranoid CVSS vector: AV:A/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
  The Best / paranoid CVSS score: 7.1

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: 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).