[CVE-2026-80629][MODERATE 7.0] octeontx2-af: npc: Fix size of entry2cntr_map [ Upstream

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

CVE: CVE-2026-80629
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: octeontx2-af: npc: Fix size of entry2cntr_map [ Upstream
Commit: de8e3a4004c5df9461974352e9d7ff0f8313c508
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=de8e3a4004c5df9461974352e9d7ff0f8313c508
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-80629
Analysis date: Fri, 28 Aug 2026 07:14:05 -0400
ActionableScore: 5
ActionableScore lower bound: 3
Actionable bucket: Strong Important candidate / Actionable Moderate at minimum
Manual review required: YES

Summary:
A slab out-of-bounds write in octeontx2 AF NPC MCAM counter mapping can occur because entry2cntr_map was allocated for bmap_entries while reserved entries can use total_entries, causing kernel memory corruption or crash on affected Marvell hardware. YES REQUIRES MANUAL CHECK.

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

The original Linux kernel CVE announcement for CVE-2026-80629 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-80629

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-2026-80629	MODERATE	CHECK WITH IMPACT FROM ORIG NN LOW	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H';*CWE-787;CWE-131;CWE-122;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:L/I:L/A:H';BEST CVSS score: '7';DESCR 'An out of bounds write in the octeontx2 AF NPC MCAM counter mapping can occur because entry2cntr_map was allocated for bmap_entries while reserved MCAM entries such as CPT 2nd pass entries can also be mapped to counters. The observed failure is a KASAN slab out of bounds write of 2 bytes in npc_map_mcam_entry_and_cntr during driver initialization, which can crash the kernel or corrupt adjacent heap metadata or objects. For the CVSS the PR:L paranoid value is used because a reduced capability root, container root, PF/VF management process, or delegated device management path may be enough in some deployments, although the ordinary trigger usually requires admin level device control. The issue is not directly network reachable from packet traffic and depends on Marvell OcteonTX2 hardware and AF NPC/CPT configuration. Impact is at least denial of service via kernel crash and in worst case may allow confidentiality or integrity impact due to kernel memory corruption.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Strong Important candidate / Actionable Moderate at minimum (with actual score 4)	YES	REMOTE WRITE KASAN OOB NETWORK HARDWARE  DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN5	YES	NO	checked

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ACTIONABLESCORE ANALYSIS
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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:

* Constrained kernel buffer overwrite: +1. The bug is a concrete KASAN-reported slab out-of-bounds write, but the write is only 2 bytes into a driver bookkeeping map.
* Memory layout invariant restoration: +1. The patch fixes an allocation-size mismatch between `bmap_entries` and `total_entries`.
* Reliable kernel crash / strong DoS: +1. The report shows a KASAN splat in `npc_map_mcam_entry_and_cntr()` during driver initialization.
* Privileged kernel/device-management memory corruption path: +1. The corruption occurs in trusted Marvell OcteonTX2 AF/NPC device-management code.
* Corruption primitive highly constrained or metadata-only: -1. The overwritten value is a counter mapping entry, not an attacker-chosen arbitrary payload.

Paranoid additions / interpretation:

* Generic memory corruption: +2 instead of only constrained overwrite. This is still an out-of-bounds slab write in kernel memory.
* Weak LPE concern: +1. Privilege escalation is not demonstrated, but kernel heap corruption in a privileged driver path should not be auto-closed without manual review.
* Typical exposure limits prevent a higher score. The path appears hardware-specific and not directly network-triggerable from packet traffic.

## 3. Reachability analysis

The observed call path is during `rvu_probe()` / `rvu_nix_init()` when the driver installs a CPT pass-2 reserved MCAM entry and maps it to a counter. In typical deployments, reliable triggering requires affected Marvell OcteonTX2 hardware and administrative control over driver load, reset, or device configuration.

This is not directly reachable from normal remote network packets. It may be influenced by privileged PF/VF or AF management paths depending on platform setup, SR-IOV configuration, mailbox exposure, and how much device control is delegated to a container, service account, or reduced-capability root. Namespaces do not make this automatically unprivileged, but delegated device-management environments can make PR closer to L than H in practical triage.

Call-site confidence: high, because the provided trace and patch show the allocation site, the failing write path, and the corrected full-range counter-map handling.

## 4. Severity interpretation

This is more than an ordinary Moderate correctness bug because the patch fixes a real slab out-of-bounds write, not just a warning or leak. Realistic exploitation evidence is limited: the write is small, metadata-oriented, hardware-specific, and not shown to provide attacker-controlled reclaim, arbitrary write, or type confusion.

Conservatively this is a borderline/manual-review Moderate. Paranoid triage should treat it as Actionable Moderate at minimum because kernel memory corruption in a privileged device-management path can be underestimated, especially if PF/VF or device management is delegated.

## 5. One-sentence report phrase

A slab out-of-bounds write in octeontx2 AF NPC MCAM counter mapping can occur because entry2cntr_map was allocated for bmap_entries while reserved entries can use total_entries, causing kernel memory corruption or crash on affected Marvell hardware. YES REQUIRES MANUAL CHECK.

## 6. Manual review recommendation

MANUAL CHECK REQUIRED.

Reason: the patch fixes a concrete KASAN-confirmed kernel slab out-of-bounds write. Even though the realistic trigger appears hardware-specific and usually privileged, the memory corruption class and possible delegated device-management reachability make auto-closure unsafe.

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

Patch: octeontx2-af: npc: Fix size of entry2cntr_map [ Upstream
Commit: de8e3a4004c5df9461974352e9d7ff0f8313c508
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=de8e3a4004c5df9461974352e9d7ff0f8313c508

Changed files:
  drivers/net/ethernet/marvell/octeontx2/af/rvu_npc.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=de8e3a4004c5df9461974352e9d7ff0f8313c508

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

The original Linux kernel CVE announcement for CVE-2026-80629 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-80629

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:H/UI:N/S:U/C:L/I:L/A:H
  The Best / paranoid CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
  The Best / paranoid CVSS score: 7

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).