[CVE-2026-46126][LOW] RDMA/mana: Fix mana_destroy_wq_obj() cleanup in mana_ib_create_qp_rss()

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

CVE: CVE-2026-46126
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: RDMA/mana: Fix mana_destroy_wq_obj() cleanup in mana_ib_create_qp_rss()
Commit: 8f23eb6c50f1a4bf32fc4d62cfb9fc39e8e586cf
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=8f23eb6c50f1a4bf32fc4d62cfb9fc39e8e586cf
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-46126
Analysis date: Thu, 28 May 2026 13:51:50 -0400
ActionableScore: 2
ActionableScore lower bound: 1
Actionable bucket: Ordinary Moderate / Low-like
Manual review required: NO

Summary:
Incorrect RDMA/mana RSS QP error unwinding can skip WQ object cleanup after specific failures, allowing a local RDMA uverbs user to leak device resources and potentially cause DoS.

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

The original Linux kernel CVE announcement for CVE-2026-46126 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-46126

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.

======================================================================
AL-KERNEL CLASSIFICATION RESULT
======================================================================

CVE-2026-46126	LOW	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:N/I:N/A:H';*CWE-772;CWE-404;CWE-459;Other CVSS 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '4.7';DESCR 'RDMA mana RSS QP creation had incorrect error unwind handling that could skip cleanup of WQ objects after mana_create_wq_obj or mana_ib_install_cq_cb failures. A local process with access to the MANA RDMA uverbs path may be able to trigger repeated failing create QP attempts and leak device or driver resources. For the CVSS the PR:L is used because triggering requires local code execution and RDMA device access, but not full host administrator privileges when RDMA is delegated to workloads. The issue is not network reachable as packet processing and does not show memory corruption, information disclosure, or privilege escalation. Impact is resource exhaustion and denial of service only, with high attack complexity because the vulnerable path depends on error conditions.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 2) 	MAYBE	SIMPLEFIX NETWORK  DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3	-	-	checked

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

ActionableScore=2
ActionableScoreLower=1

## 1. ActionableScore

* Conservative score: **1**
* Paranoid score: **2**
* Final recommended bucket: **Ordinary Moderate / Low-like**::

## 2. Signal breakdown

* Local unprivileged trigger: **+1**. A local process with access to the MANA RDMA uverbs interface may trigger RSS QP creation.
* Availability impact realistic, paranoid only: **+1**. Repeated failures may leak WQ or GDMA device resources and eventually cause local RDMA resource exhaustion.
* Hard or special error path: **-1**. The bug requires specific failure conditions in `mana_create_wq_obj()` or `mana_ib_install_cq_cb()`, not just ordinary successful QP creation.
* Rare or device-specific exposure: **-1 conservative**. The issue requires MANA RDMA hardware or virtual device exposure and accessible uverbs.
* No memory corruption: **+0**. The patch fixes cleanup accounting and missing destroy calls, not UAF, OOB write, heap overwrite, or double-free.
* No confidentiality or integrity signal: **+0**. No leak, write primitive, privilege escalation, or boundary bypass is shown.

## 3. Reachability analysis

The bug is local and requires access to the MANA RDMA userspace interface. It is not remotely reachable through packet processing. Containers may matter if the MANA RDMA device is delegated to a tenant or workload, but the trigger still depends on local RDMA object creation and error-path behavior. The affected path is not default on systems without MANA RDMA devices or without uverbs access.

## 4. Severity interpretation

This behaves like a **Low-like or ordinary Moderate** resource cleanup issue. The realistic impact is constrained resource leakage on failing RSS QP creation paths. There is no supported memory corruption, information disclosure, or privilege escalation primitive. It should not be treated as Important without evidence that untrusted users can reliably force the failing path and exhaust system-wide resources.

## 5. One-sentence report phrase

Incorrect RDMA/mana RSS QP error unwinding can skip WQ object cleanup after specific failures, allowing a local RDMA uverbs user to leak device resources and potentially cause DoS.

## 6. Manual review recommendation

**NO MANUAL CHECK NEEDED**

This is a constrained RDMA error-path resource leak with no demonstrated memory corruption, information leak, or LPE path.

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

Patch: RDMA/mana: Fix mana_destroy_wq_obj() cleanup in mana_ib_create_qp_rss()
Commit: 8f23eb6c50f1a4bf32fc4d62cfb9fc39e8e586cf
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=8f23eb6c50f1a4bf32fc4d62cfb9fc39e8e586cf

Commit description:

Sashiko points out there are two bugs here in the error unwind flow, both
related to how the WQ table is unwound.

First there is a double i-- on the first failure path due to the while loop
having a i--, remove it.

Second if mana_ib_install_cq_cb() fails then mana_create_wq_obj() is not
undone due to the above i--.

Cc: stable@vger.kernel.org
Fixes: c15d780 ("RDMA/mana_ib: Add CQ interrupt support for RAW QP")
Link: https://sashiko.dev/#/patchset/0-v2-1c49eeb88c48%2B91-rdma_udata_rep_jgg%40nvidia.com?part=1
Link: https://patch.msgid.link/r/6-v1-41f3135e5565+9d2-rdma_ai_fixes1_jgg@nvidia.com
Reviewed-by: Long Li <longli@microsoft.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Changed files:
  drivers/infiniband/hw/mana/qp.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=8f23eb6c50f1a4bf32fc4d62cfb9fc39e8e586cf

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

The original Linux kernel CVE announcement for CVE-2026-46126 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-46126

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: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: 1
  Paranoid ActionableScore: 2

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).