[CVE-2026-90424][LOW] iommu/tegra241-cmdqv: Fix VINTF0 leak on the init-failure path [ Upstream

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

CVE: CVE-2026-90424
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: iommu/tegra241-cmdqv: Fix VINTF0 leak on the init-failure path [ Upstream
Commit: 1d2271d7df5230e4ce36bdafd17524bd004f3b3f
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=1d2271d7df5230e4ce36bdafd17524bd004f3b3f
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-90424
Analysis date: Fri, 18 Sep 2026 03:23:16 -0400
ActionableScore: 0
ActionableScore lower bound: unknown
Actionable bucket: Ordinary Moderate
Manual review required: NO

Summary:
No one-sentence report phrase was found.

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

The original Linux kernel CVE announcement for CVE-2026-90424 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-90424

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-2026-90424	LOW	https://www.kernelcve.org/list/?q=CVE-2026-90424 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:H/UI:N/S:U/C:N/I:N/A:H';*CWE-401;*CWE-772;CWE-459;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '4.1';DESCR 'A memory leak can occur in the Tegra241 CMDQV init failure path when VINTF0 is allocated but not reachable by the normal probe unwind logic. A later VCMDQ preallocation failure can also leave VINTF0 published before the hardware ownership state is finalized, causing cleanup to make the wrong ownership decision and skip the in kernel free path. For the CVSS the PR:H is selected because reliable triggering normally requires administrative control over driver probing, device bind or unbind, or a fault condition in the platform device initialization path. The issue is not network reachable. Impact is denial of service only through resource leakage, and there is no evidence of UAF, OOB access, arbitrary write, information disclosure, or privilege escalation.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 0)	YES	INIT LEAK ERRORPATH LINUS 	YES	NO	checked

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

ActionableScore=0
PrimitiveClass=NONE
RealUAF=NO
HostAdminRequired=YES
NamespaceScopedPrivilege=NO
ImportantCandidate=NO
ManualReview=NO
AutoDowngradeAllowed=YES

1. ActionableScore

* Raw conservative score: -1
* Conservative score: 0
* Raw paranoid score: 0
* Paranoid score: 0
* Applied conservative floor/cap: raw score bounded at 0 because actionable scores should not go negative.
* Applied paranoid floor/cap: none.
* Final recommended bucket: **Ordinary Moderate**::

2. Signal breakdown

Positive signals:

* +1 Concrete persistent kernel resource/reference leak: VINTF0 can be allocated and then missed by normal probe unwind when `tegra241_cmdqv_init_vintf()` fails before publishing it into `cmdqv->vintfs[]`. A later VCMDQ preallocation failure can also cause cleanup to skip the in-kernel free path because ownership was derived from `hyp_own` before the hardware read-back initialized it.
* +1 paranoid sustained resource exhaustion concern was considered but not awarded conservatively. It is only weakly supported because repeated accumulation would require repeated init/probe failure cycles on a specific platform driver path, not an ordinary attacker-controlled runtime operation.

Negative signals:

* -2 Host-admin-equivalent triggering requirement: reliable triggering appears to require administrative control over platform driver probing, device bind/unbind, fault injection into the init path, or equivalent host/device-management control.

Important non-awarded signals:

* No RealUAF: the patch establishes missing frees and ownership cleanup confusion, not stale post-free use.
* No concrete repeated release/refcount operation: there is no visible first release that may destroy an object followed by a second lifetime mutation on the same dangling reference.
* No controlled reclaim, arbitrary write, OOB access, callback control, information disclosure, or privilege escalation is established.
* Reliable kernel crash / strong DoS was not awarded because the demonstrated issue is a leak on init-failure paths, not an immediate host-wide crash.
* Extra Availability was not awarded because persistent host-wide exhaustion is not established for a below-host-admin attacker.
* Remote reachability was not awarded.

3. Reachability analysis

The vulnerable path is in the NVIDIA Tegra241 CMDQV support under the ARM SMMU v3 IOMMU driver. The affected operation occurs during driver/device initialization and failure unwind, not through a normal unprivileged syscall, network packet path, or namespace-scoped interface.

A practical attacker would need to influence driver probe failure, device bind/unbind, platform initialization state, memory allocation failure timing, or hardware/firmware behavior. Those actions are normally host-admin-equivalent or outside an ordinary local attacker model. The complete trigger chain is not namespace-scoped. No network reachability is supported. The hardware is platform-specific, but no separate rare-hardware penalty is needed because the host-admin/device-management restriction already captures the practical reachability limitation.

Race repeatability is not relevant here. The issue is an ordered init-failure cleanup bug rather than a timing race.

4. Primitive and severity interpretation

The exact primitive is a persistent kernel memory/resource leak caused by incorrect cleanup ownership decisions for VINTF0 and its logical VCMDQ allocations on init-failure paths.

This is not active structured UAF and not fixed stale storage. It is a cleanup/resource-management defect where a kernel-owned object may not be freed because it is either not yet published to the normal unwind path or is misclassified as guest-owned before `hyp_own` is initialized from hardware state.

PrimitiveClass=NONE because no corruption, stale use, authorization bypass, COW violation, or security-boundary primitive is established. The demonstrated consequence is resource leakage. The speculative consequence is denial of service through repeated accumulation, but reliable accumulation appears to require host-admin-level driver or platform control.

ImportantCandidate=NO because there is no unresolved memory-corruption or boundary-bypass primitive requiring Important-vs-Moderate preservation. AutoDowngradeAllowed=YES because this is a constrained resource leak with no UAF, no repeated lifetime mutation, no controlled corruption, and no below-host-admin trigger shown.

Likely operational severity is Low-like or ordinary Moderate at most.

5. One-sentence report phrase

A Tegra241 CMDQV init-failure cleanup bug can leak VINTF0 or related VCMDQ resources when ownership is decided from uninitialized hardware state, but practical triggering appears host-admin controlled and the impact is limited to resource leakage.

6. Manual review recommendation

NO MANUAL CHECK NEEDED

The patch shows a concrete memory leak but no UAF, no repeated release/refcount mutation, no security-boundary bypass, no network path, and no below-host-admin trigger.

7. Call-site confidence

Call-site confidence: high

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

Patch: iommu/tegra241-cmdqv: Fix VINTF0 leak on the init-failure path [ Upstream
Commit: 1d2271d7df5230e4ce36bdafd17524bd004f3b3f
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=1d2271d7df5230e4ce36bdafd17524bd004f3b3f

Changed files:
  drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.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=1d2271d7df5230e4ce36bdafd17524bd004f3b3f

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

The original Linux kernel CVE announcement for CVE-2026-90424 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-90424

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:H/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS score: 4.1

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: unknown
  Paranoid ActionableScore: 0

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).