[CVE-2026-53044][MODERATE REGULAR] soc/tegra: cbb: Fix incorrect ARRAY_SIZE in fabric lookup tables [ Upstream

[CVE-2026-53044][MODERATE REGULAR] soc/tegra: cbb: Fix incorrect ARRAY_SIZE in fabric lookup tables [ Upstream

[AL-KERNEL]

CVE: CVE-2026-53044
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: soc/tegra: cbb: Fix incorrect ARRAY_SIZE in fabric lookup tables [ Upstream
Commit: f46870b451f7583802ed26eec8b93e138840fcd9
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=f46870b451f7583802ed26eec8b93e138840fcd9
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53044
Analysis date: Thu, 25 Jun 2026 14:20:55 -0400
ActionableScore: 3
ActionableScore lower bound: 1
Actionable bucket: Borderline, manual review recommended
Manual review required: YES

Summary:
Incorrect ARRAY_SIZE values in Tegra CBB fabric lookup tables may allow an out-of-bounds read during target timeout handling, with practical impact mainly limited to SoC-specific diagnostic failure or DoS and only weak confidentiality concern through possible logged adjacent data.

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

The original Linux kernel CVE announcement for CVE-2026-53044 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53044

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 REGULAR
Manual review required: YES

A detailed explanation of the methodology and priority rules is included
at the end of this message.

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

CVE-2026-53044	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:N/A:H';CWE-125;CWE-129;*CWE-787;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '5.3';DESCR 'An incorrect ARRAY_SIZE value in Tegra CBB fabric lookup tables can make the target timeout lookup iterate past the end of the real target_map array. This is an out-of-bounds read in a SoC specific diagnostic path rather than an obvious write primitive or UAF. For the CVSS the PR:L is used for the paranoid score because some deployments may expose device or driver paths to a reduced capability local user or service account that can trigger hardware error handling, although typical reliable triggering is more privileged. The issue is not network reachable and requires local interaction with Tegra hardware behavior or driver controlled timeout conditions. Impact is mainly denial of service or incorrect fault reporting, with limited confidentiality risk only if out-of-bounds static data becomes observable through logs.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline, manual review recommended (with actual score 2) 	MAYBE	OOB SIMPLEFIX LINUS  LOWERED_FROM_HIGH_BASED_ON_GUESSCVSS  DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN5	-	-	checked

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

ActionableScore=3
ActionableScoreLower=1

## 1. ActionableScore

* Conservative score: **1**
* Paranoid score: **3**
* Final recommended bucket: **Borderline, manual review recommended**

## 2. Signal breakdown

Paranoid scoring:

* **Firmware-mediated external influence: +1**
  The affected path is reached during Tegra CBB target timeout handling, which may depend on hardware, firmware, or device-originated fabric error conditions.

* **Privileged kernel/device-management memory corruption path: +1**
  The bug is in SoC fabric/device error handling code and causes an incorrect lookup-table bound during trusted kernel diagnostic processing.

* **Availability impact realistic: +1**
  An out-of-bounds read during timeout lookup could plausibly produce a kernel warning, incorrect fault handling, or crash, although reliability is not demonstrated.

* **Confidentiality impact plausible: +1**
  Limited adjacent static data exposure is possible only if the out-of-bounds lookup result is later printed or otherwise exposed through logs. This is weak and not a demonstrated leak.

* **Hard or special trigger condition: -1**
  Triggering requires Tegra-specific CBB timeout behavior and likely depends on hardware or driver error paths, not an ordinary syscall or network input.

Conservative scoring:

* **Privileged device-management kernel path: +1**
* **Availability impact plausible: +1**
* **Special SoC/hardware-dependent reachability: -1**

No strong memory corruption score is applied because the patch shows an incorrect array size causing likely out-of-bounds read, not OOB write, UAF, double-free, refcount reuse, or attacker-controlled overwrite.

## 3. Reachability analysis

The likely trigger is local or firmware/device-mediated through Tegra CBB target timeout handling. A normal remote attacker cannot directly reach this path over the network. Typical reliable triggering may require privileged control over device state, a buggy or malicious device/firmware path, or a workload capable of provoking fabric timeout conditions on affected Tegra SoCs.

Namespaces and containers probably do not materially lower privileges unless a container or service is delegated direct device access that can influence the relevant hardware path. The subsystem is SoC-specific and not broadly deployed across generic Linux systems.

## 4. Severity interpretation

This behaves more like a **Low-like or ordinary Moderate issue with manual-review value**, not an Important-class vulnerability. The theoretical concern is kernel out-of-bounds read in a trusted device-management path. The realistic evidence points mainly to incorrect fault reporting or DoS under Tegra-specific timeout conditions.

There is no demonstrated privilege-escalation primitive, no write primitive, no UAF, and no network reachability. The paranoid score is raised only to avoid auto-closing a kernel OOB access in hardware error handling before a human checks exact table sizes, adjacent data, and log exposure.

## 5. One-sentence report phrase

Incorrect ARRAY_SIZE values in Tegra CBB fabric lookup tables may allow an out-of-bounds read during target timeout handling, with practical impact mainly limited to SoC-specific diagnostic failure or DoS and only weak confidentiality concern through possible logged adjacent data.

## 6. Manual review recommendation

**MANUAL CHECK RECOMMENDED**

Manual review is recommended because this is a kernel out-of-bounds access in a device-management path, but it does not currently justify Important treatment without evidence of write corruption, reliable crash, sensitive disclosure, or unprivileged reachable triggering.

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

Patch: soc/tegra: cbb: Fix incorrect ARRAY_SIZE in fabric lookup tables [ Upstream
Commit: f46870b451f7583802ed26eec8b93e138840fcd9
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=f46870b451f7583802ed26eec8b93e138840fcd9

Changed files:
  drivers/soc/tegra/cbb/tegra234-cbb.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=f46870b451f7583802ed26eec8b93e138840fcd9

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

The original Linux kernel CVE announcement for CVE-2026-53044 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53044

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:L/I:N/A:H
  The Best / paranoid CVSS score: 5.3

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: 3

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 REGULAR

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).