[CVE-2026-46084][MODERATE 7.0] RDMA/mana_ib: Disable RX steering on RSS QP destroy [ Upstream

[CVE-2026-46084][MODERATE 7.0] RDMA/mana_ib: Disable RX steering on RSS QP destroy [ Upstream

[AL-KERNEL]

CVE: CVE-2026-46084
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: YES
Patch: RDMA/mana_ib: Disable RX steering on RSS QP destroy [ Upstream
Commit: 6a2d6273b6c3581ce7b90ce17b5cbb4efd19438f
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=6a2d6273b6c3581ce7b90ce17b5cbb4efd19438f
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-46084
Analysis date: Wed, 27 May 2026 13:22:07 -0400
ActionableScore: 5
ActionableScore lower bound: 4
Actionable bucket: Strong Important candidate / Actionable Moderate at minimum
Manual review required: NO

Summary:
A stale MANA firmware RX steering configuration after RSS QP destruction can route incoming completions to reused CQ IDs, causing local device disruption or DoS with limited object-confusion concern on affected RDMA VF deployments.

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

The original Linux kernel CVE announcement for CVE-2026-46084 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-46084

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: 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-2026-46084	MODERATE	CHECK	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:H';*CWE-672;*CWE-664;CWE-362;CWE-404;Other CVSS 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '5.8';DESCR 'A stale firmware steering lifetime bug can occur in MANA RDMA when an RSS QP is destroyed without disabling vPort RX steering first. Firmware can continue routing incoming RX completions to CQ IDs that belonged to destroyed RX objects, and those IDs may later be reused by the ethernet driver for TX CQs after mana_open(). For the CVSS the PR:L is used because a local process with access to the RDMA or DPDK path can create and destroy the RSS QP, while reliable triggering also depends on the VF being brought up and traffic arriving from a peer VM. The issue is not a direct network parser bug, but peer traffic can influence the stale firmware completion path. Impact is mainly denial of service or device datapath disruption. A limited confidentiality or integrity concern is kept only for paranoid review because completions can land on reused CQ objects, but the patch does not show UAF reclaim, arbitrary write, or privilege escalation.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Strong Important candidate / Actionable Moderate at minimum (with actual score 5) 	MAYBE	ERRORPATH NETWORK  KPANIC INCREASED_FROM_LOW_BASED_ON_REQUIREMANUALCHECK	-	-	checked

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

ActionableScore=5
ActionableScoreLower=4

## 1. ActionableScore

* Conservative score: 4
* Paranoid score: 5
* Final recommended bucket: **Strong Important candidate / Actionable Moderate at minimum**::

## 2. Signal breakdown

* Firmware-mediated external influence: +1
  Incoming peer traffic can continue to be steered by firmware using stale RX steering state after RSS QP teardown.

* Local trigger: +1
  A local process with access to the RDMA or DPDK path can create and destroy the RSS QP. This is not a pure remote trigger.

* Real lifetime corruption: +1
  Firmware keeps references to RX objects or CQ IDs after the driver has destroyed the corresponding RX WQ objects.

* Privileged kernel/device-management lifetime path: +1
  The bug is in a trusted RDMA and ethernet device-management path involving firmware steering, queues, CQs, and VF lifecycle.

* Availability impact realistic: +1
  RX completions can be delivered to reused or unexpected CQ IDs, causing driver warnings, CQ lookup failures, datapath disruption, or device reset style DoS.

* Weak LPE or C/I concern: +1 paranoid only
  Reused CQ IDs receiving completions for the wrong queue type is a plausible object-confusion concern, but the patch does not show controlled overwrite, UAF reclaim, or a privilege escalation primitive.

* Hard or configuration-dependent trigger: -1
  Reliable triggering requires MANA hardware or Azure VF context, RDMA RSS QP usage, teardown, subsequent `mana_open()`, and concurrent peer traffic.

* No direct memory corruption primitive: +0
  The patch does not demonstrate arbitrary write, heap overwrite, double free, or controlled kernel memory reuse.

## 3. Reachability analysis

The attacker is local and needs access to the MANA RDMA or user-mode networking path, such as DPDK or RDMA resources. Peer traffic is relevant, but the issue is not a direct network parser vulnerability because the stale state is created by local QP teardown and firmware steering state. Containers may matter if RDMA devices or VF access are delegated into them. The issue is hardware and cloud-environment dependent, mainly affecting systems using Microsoft Azure Network Adapter with `mana_ib`.

## 4. Severity interpretation

This is best treated as Actionable Moderate. The realistic impact is device datapath disruption or local DoS caused by stale firmware steering to destroyed queues and reused CQ IDs. The theoretical concern is object confusion through completions landing on reused CQ objects, but the patch does not show a reliable confidentiality, integrity, or privilege escalation primitive. It should not be auto-closed because firmware-mediated stale lifetime bugs can be underestimated.

## 5. One-sentence report phrase

A stale MANA firmware RX steering configuration after RSS QP destruction can route incoming completions to reused CQ IDs, causing local device disruption or DoS with limited object-confusion concern on affected RDMA VF deployments.

## 6. Manual review recommendation

MANUAL CHECK RECOMMENDED.

The issue is hardware-specific and not directly remote, but it involves stale firmware references to destroyed queue objects and reused CQ IDs, so it deserves manual review for device-state corruption and DoS impact.

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

Patch: RDMA/mana_ib: Disable RX steering on RSS QP destroy [ Upstream
Commit: 6a2d6273b6c3581ce7b90ce17b5cbb4efd19438f
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=6a2d6273b6c3581ce7b90ce17b5cbb4efd19438f

Changed files:
  drivers/infiniband/hw/mana/qp.c
  drivers/net/ethernet/microsoft/mana/mana_en.c
  include/net/mana/mana.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=6a2d6273b6c3581ce7b90ce17b5cbb4efd19438f

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

The original Linux kernel CVE announcement for CVE-2026-46084 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-46084

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:N/I:N/A:H
  The Best / paranoid CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:H
  The Best / paranoid CVSS score: 5.8

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: 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).