[CVE-2026-68417][MODERATE 7.0] RDMA/siw: publish QP after initialization [ Upstream

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

CVE: CVE-2026-68417
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: RDMA/siw: publish QP after initialization [ Upstream
Commit: 36e91a58397ca8c978e38a0bf389f0c6113fa8ca
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=36e91a58397ca8c978e38a0bf389f0c6113fa8ca
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68417
Analysis date: Mon, 10 Aug 2026 14:19:31 -0400
ActionableScore: 5
ActionableScore lower bound: 3
Actionable bucket: Actionable Moderate at minimum
Manual review required: YES

Summary:
RDMA SIW can publish a QP before full initialization, allowing a concurrent QPN lookup to observe incomplete queues, CQ pointers, state, or completion fields and potentially crash the kernel or corrupt RDMA object state.

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

The original Linux kernel CVE announcement for CVE-2026-68417 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68417

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

CVE-2026-68417	MODERATE	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:L/I:L/A:H';CWE-362;CWE-665;CWE-908;Other CVSS 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '5.8';DESCR 'RDMA siw published a queue pair through siw_qp_add before queues, CQ pointers, state, completion, tx_cpu, and device list state were fully initialized. A concurrent QPN lookup can therefore observe a partially constructed QP and may use fields that are still NULL or not ready, which can lead to a kernel crash or inconsistent QP handling. For the CVSS the PR:L is used for the paranoid score because reliable triggering appears possible for a local user or reduced privilege service with access to RDMA resources. The issue is not expected to be Internet wide and is mainly relevant on systems where soft iWARP is enabled and used on local or data center networks. Impact is at least denial of service. Because this is a publication before initialization race in a networked RDMA object, limited confidentiality or integrity impact is kept in the paranoid score for manual review sensitivity.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Actionable Moderate at minimum (with actual score 4)	YES	READ DANGER INIT NETWORK HARDWARE  DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN5	NO	NO	checked

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

ActionableScore=5
ActionableScoreLower=3

## 1. ActionableScore

* Conservative score: 3
* Paranoid score: 5
* Final recommended bucket: **Actionable Moderate at minimum**

## 2. Signal breakdown

Conservative signals:

* Local unprivileged trigger: +1. QP creation is reachable from local RDMA userspace when SIW and uverbs access are available.
* Memory corruption, weak/indirect corruption candidate: +1. A QPN lookup can observe a partially initialized QP with queues, CQ pointers, state, completion, tx_cpu, or list state not ready.
* Reliable kernel crash / strong DoS: +1. Use of a partially constructed QP can plausibly lead to NULL dereference or inconsistent QP handling.
* RDMA device object API with object lifetime exposure: +1. The bug is not just configuration. It publishes a kernel RDMA object before initialization is complete.
* Hard or unreliable race / special timing required: -1. The vulnerable lookup must race with QP construction.

Paranoid additional signals:

* Weak LPE concern: +1. The object is visible before full initialization and may be consumed by other RDMA paths, but there is no demonstrated reclaim, overwrite, callback control, or refcount takeover.
* Integrity impact plausible: +1. Incorrect use of a partially initialized QP could affect RDMA object state, but this remains a manual-review concern rather than a proven primitive.

Not counted:

* Remote reachable: +0. SIW is network based, but the patch does not show that a remote peer can reliably trigger the QPN lookup window without local QP creation or knowledge of the transient QPN.
* Strong memory corruption primitive: +0. No UAF reclaim, OOB write, arbitrary write, double free, or type confusion is shown.
* Broad/default exposure: +0. SIW is not a universally enabled default path.

Call-site confidence: medium. The patch shows the vulnerable publication point and initialization order, but not all QPN lookup consumers.

## 3. Reachability analysis

The likely trigger is a local user or service able to create RDMA SIW queue pairs through uverbs or another RDMA management path. In typical deployments this may require membership in an RDMA-capable environment or device-node access, but not necessarily full host root.

Containers and namespaces matter if RDMA device access is delegated into a container or service sandbox. In that case, the practical PR should be treated closer to PR:L rather than PR:H, because the attacker may not have full host administrative privileges.

The issue is not clearly Internet-reachable. SIW uses TCP, but the vulnerable operation is publication of a local kernel QP before construction completes. A remote peer may influence RDMA activity only after suitable local setup and timing conditions.

## 4. Severity interpretation

This is not an ordinary low-risk cleanup because it exposes a partially initialized kernel RDMA object to lookup paths. Realistic impact is most strongly supported as local DoS through crash or invalid object use.

Theoretical memory corruption or privilege escalation concern exists only weakly. The patch does not show attacker-controlled reclaim, writable stale object access, callback hijack, or arbitrary write. Therefore the conservative score stays borderline, while the paranoid score reaches Actionable Moderate for manual-review sensitivity.

## 5. One-sentence report phrase

RDMA SIW can publish a QP before full initialization, allowing a concurrent QPN lookup to observe incomplete queues, CQ pointers, state, or completion fields and potentially crash the kernel or corrupt RDMA object state.

## 6. Manual review recommendation

MANUAL CHECK REQUIRED

YES REQUIRES MANUAL CHECK. This is a race in RDMA object publication with a plausible crash and weak corruption concern, even though no strong LPE primitive is demonstrated by the patch.

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

Patch: RDMA/siw: publish QP after initialization [ Upstream
Commit: 36e91a58397ca8c978e38a0bf389f0c6113fa8ca
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=36e91a58397ca8c978e38a0bf389f0c6113fa8ca

Changed files:
  drivers/infiniband/sw/siw/siw_verbs.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=36e91a58397ca8c978e38a0bf389f0c6113fa8ca

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

The original Linux kernel CVE announcement for CVE-2026-68417 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68417

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: 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).