[CVE-2026-80667][LOW] net/mlx5: LAG, MPESW, Fix missing complete() on devcom error [ Upstream

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

CVE: CVE-2026-80667
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: net/mlx5: LAG, MPESW, Fix missing complete() on devcom error [ Upstream
Commit: 68cdbe498da8475cfd49591954e3db8fc6582eda
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=68cdbe498da8475cfd49591954e3db8fc6582eda
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-80667
Analysis date: Fri, 28 Aug 2026 07:28:30 -0400
ActionableScore: 1
ActionableScore lower bound: 0
Actionable bucket: Ordinary Moderate / Low-like
Manual review required: NO

Summary:
mlx5 LAG/MPESW work handling could leave a waiting caller blocked indefinitely when the devcom component is missing, causing a local driver control path denial of service without evidence of memory corruption or privilege escalation.

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

The original Linux kernel CVE announcement for CVE-2026-80667 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-80667

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: LOW
Manual review required: NO

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
======================================================================

CVE-2026-80667	LOW	CHECK WITH IMPACT FROM ORIG NN MODERATE	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H';*CWE-833;CWE-703;CWE-667;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '4.7';DESCR 'mlx5 LAG/MPESW work handling can leave a caller blocked indefinitely because mlx5_mpesw_work returns early when the devcom component is missing and does not signal the completion object. A caller that queued the work and waits on mpesww comp may never be woken, causing a local denial of service in the driver control path. For the CVSS the PR:L is used for the paranoid score because some deployments may delegate network device administration to a reduced capability root, container root, or service account rather than full host root. The issue is not directly network reachable and is not triggered by ordinary packet traffic. Impact is availability loss only, with no evidence of memory corruption, information disclosure, or privilege escalation.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 1)  SKIP CVE-2026-80667 UNKNOWN SKIP No affected files built, so skip this CVE NO  - - unknown 	MAYBE	REMOTE SIMPLEFIX NETWORK  DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3	-	-	checked

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

ActionableScore=1
ActionableScoreLower=0

## 1. ActionableScore

* Conservative score: 0
* Paranoid score: 1
* Final recommended bucket: **Ordinary Moderate / Low-like**

## 2. Signal breakdown

Conservative signals:

* Reliable kernel crash / strong DoS: +0. The patch shows an indefinite wait in a driver control path, not a demonstrated kernel panic or system-wide crash.
* Availability impact realistic: +1. A caller waiting on `mpesww->comp` can block indefinitely if `mlx5_lag_get_devcom_comp()` returns NULL.
* Requires admin/root/CAP_* in typical deployments: -2. Triggering this path typically requires mlx5 LAG/MPESW configuration, reset, devlink, bonding, or other privileged network-device management.
* Rare AND difficult-to-reach subsystem/configuration: -1. The affected path is specific to mlx5 LAG/MPESW and devcom error handling, not ordinary packet processing.
* Floor at 0.

Paranoid adjustment:

* Local reduced-privilege device administration possible: +1. In some deployments, network-device management may be delegated to a service account, container root, or reduced-capability administrator, making PR:L a defensible paranoid interpretation.
* No memory corruption, UAF, OOB, refcount issue, info leak, or privilege escalation signal is supported.

## 3. Reachability analysis

The bug is reachable through mlx5 LAG/MPESW driver control paths when work is queued and a caller waits for completion. It is not directly network reachable and ordinary packet traffic is not a realistic trigger. In typical deployments, the relevant operations require host administrative privileges or CAP_NET_ADMIN-like control over the Mellanox device. Namespaces or containers may lower practical privileges only if device or network administration is explicitly delegated.

Call-site confidence: medium. The patch shows the completion object and the early return, but not all callers that queue and wait for this work.

## 4. Severity interpretation

This behaves like a Low-like or ordinary Moderate availability issue. The realistic impact is a blocked control-plane operation or driver-management hang. There is no evidence of memory corruption, confidentiality impact, integrity impact, or privilege escalation. The paranoid score remains low because the only meaningful escalation is from full admin to delegated network-device management, not from DoS to memory corruption.

## 5. One-sentence report phrase

mlx5 LAG/MPESW work handling could leave a waiting caller blocked indefinitely when the devcom component is missing, causing a local driver control path denial of service without evidence of memory corruption or privilege escalation.

## 6. Manual review recommendation

NO MANUAL CHECK NEEDED

This can be autoclosable for security triage unless the product exposes mlx5 LAG/MPESW management to untrusted reduced-privilege tenants.

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

Patch: net/mlx5: LAG, MPESW, Fix missing complete() on devcom error [ Upstream
Commit: 68cdbe498da8475cfd49591954e3db8fc6582eda
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=68cdbe498da8475cfd49591954e3db8fc6582eda

Changed files:
  drivers/net/ethernet/mellanox/mlx5/core/lag/mpesw.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=68cdbe498da8475cfd49591954e3db8fc6582eda

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

The original Linux kernel CVE announcement for CVE-2026-80667 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-80667

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:N/I:N/A:L
  The Best / paranoid CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS score: 4.7

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: 0
  Paranoid ActionableScore: 1

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: LOW
KPANIC detected for this report: NO
Published priority for this report (same as in Subject): LOW

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).