[CVE-2026-97572][MODERATE REGULAR] bnxt_en: Propagate RX ring init failures in bnxt_init_nic()

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

CVE: CVE-2026-97572
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: bnxt_en: Propagate RX ring init failures in bnxt_init_nic()
Commit: daadccd062fdca5e77a8cc22ffe35857803b6c49
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=daadccd062fdca5e77a8cc22ffe35857803b6c49
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-97572
Analysis date: Fri, 25 Sep 2026 13:57:45 -0400
ActionableScore: 2
ActionableScore lower bound: 1
Actionable bucket: Ordinary Moderate
Manual review required: NO

Summary:
A failed RX ring allocation in bnxt_en can be ignored and allow TPA to use partially initialized entries with a zero DMA address, potentially causing device malfunction or a constrained DMA fault, but attacker-controlled memory corruption is not established.

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

The original Linux kernel CVE announcement for CVE-2026-97572 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-97572

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: 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
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CVE-2026-97572	MODERATE	https://www.kernelcve.org/list/?q=CVE-2026-97572 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:H/I:H/A:H';CWE-252;CWE-703;CWE-665;*CWE-787;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:L/I:L/A:H';BEST CVSS score: '7';DESCR 'A failed RX ring allocation in the Broadcom bnxt_en driver can be ignored by bnxt_init_nic. TPA can then be enabled while RX TPA entries remain partially initialized, allowing a zero DMA address to be supplied to the device. This may cause a kernel crash and can plausibly result in device initiated memory corruption depending on DMA and IOMMU configuration. For the CVSS the PR:L in the paranoid score reflects environments where a local reduced capability account, container root, or service account can control network interface recovery or create resource pressure. The issue is not directly network reachable through ordinary packet traffic. Reliable triggering requires a specific allocation failure during RX ring initialization and subsequent TPA activity. Impact is at least local denial of service and in the worst case may include confidentiality and integrity impact from invalid DMA. ';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 2)	YES	REMOTE OOB INIT SIMPLEFIX NETWORK DMAorINTERRUPT  DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN4	NO	NO	checked

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

ActionableScore=2
ActionableScoreLower=1
PrimitiveClass=CLASS_C
RealUAF=NO
HostAdminRequired=UNKNOWN
NamespaceScopedPrivilege=UNKNOWN
ImportantCandidate=NO
ManualReview=RECOMMENDED
AutoDowngradeAllowed=YES

## 1. ActionableScore

* Raw conservative score: 1
* Conservative score: 1
* Raw paranoid score: 2
* Paranoid score: 2
* Final recommended bucket: **Ordinary Moderate**::

No floor or cap was applied.

## 2. Signal breakdown

Conservative signals:

* +1 Weak indirect corruption candidate. An RX ring allocation failure can leave `rxr->rx_tpa[]` partially zeroed, while TPA is subsequently enabled. The commit explicitly states that this can hand a zero DMA address to the device.

Paranoid signals:

* +1 Constrained kernel buffer overwrite or invalid DMA operation. If the affected hardware performs DMA using the zero descriptor address instead of rejecting it, this could produce a fixed and highly constrained invalid DMA access. The patch does not establish attacker-selected DMA target, payload, descriptor reuse, or a successful memory overwrite.

Important non-awarded signals:

* No real UAF, stale object, double free, or repeated release/refcount mutation is established.
* Controlled DMA target selection is not demonstrated. The problematic address is zeroed or fixed rather than attacker-directed.
* Arbitrary kernel write is not demonstrated.
* Kernel crash or host-wide DoS is plausible but not explicitly demonstrated by the supplied commit, so no reliable crash point is awarded.
* Remote reachability is not established. Ordinary network traffic is not shown to cause the RX ring allocation failure or NIC initialization sequence.
* Local unprivileged reachability is not established.
* No confidentiality, integrity, privilege-escalation, or security-boundary-bypass consequence is demonstrated.
* No host-admin penalty is applied because the complete privilege boundary for triggering ring initialization failure is not established.
* No hardware-specific or niche-subsystem penalty is applied because the affected bnxt_en driver alone does not prove rare hardware or unreachable configuration.

## 3. Reachability analysis

The vulnerable state requires failure of `bnxt_alloc_one_rx_ring()` during RX ring initialization, followed by continued NIC initialization and TPA operation. The supplied patch does not show which actor can reliably force the allocation failure, trigger adapter reset or initialization, or cause traffic to reach the affected aggregation entry.

A local administrator, network-management service, or recovery workflow may be able to influence interface initialization or reset operations, but this is not enough to establish that host-admin privilege is required for the complete trigger. Conversely, the evidence does not establish that an ordinary user, container user, or namespace-local `CAP_NET_ADMIN` holder can force the required allocation failure and subsequent TPA activity.

No namespace-scoped complete trigger chain is shown. No special boot parameter, sysctl, firmware compromise, or prior privileged setup is explicitly required by the supplied material. The issue is hardware and driver dependent, but the material does not establish a rare physical-only requirement. There is no race condition in the demonstrated control flow. It is an ordered error-handling failure.

## 4. Primitive and severity interpretation

The patch establishes an invalid-state bug: `bnxt_init_nic()` ignored an RX-ring initialization error and enabled later NIC functionality despite partially initialized RX TPA state. A zero DMA address may then be passed to the network device when a zeroed TPA entry is used.

This is not a UAF, lifetime violation, ownership violation, or repeated refcount mutation. It is also not an established arbitrary or directed DMA write. The patch does not show that the device necessarily performs a write through address zero, that an attacker controls the transferred data, or that address zero maps to attacker-useful host memory. Therefore the demonstrated primitive is best classified as CLASS_C invalid-state behavior with a possible constrained DMA fault or constrained memory-corruption outcome.

The practical demonstrated consequence is driver or device malfunction. Kernel crash or host DoS is plausible if the hardware or DMA subsystem faults on the invalid DMA descriptor, but it is not directly documented in the supplied evidence. The paranoid score preserves this uncertainty as a constrained DMA-corruption candidate, not as demonstrated arbitrary kernel memory corruption.

ImportantCandidate is NO because no meaningful exploitation leverage beyond the invalid DMA state is established. AutoDowngradeAllowed is YES because there is no real UAF, controlled overwrite, attacker-selected target, security boundary bypass, or unresolved repeated lifetime mutation requiring Important-class preservation.

## 5. One-sentence report phrase

A failed RX ring allocation in bnxt_en can be ignored and allow TPA to use partially initialized entries with a zero DMA address, potentially causing device malfunction or a constrained DMA fault, but attacker-controlled memory corruption is not established.

## 6. Manual review recommendation

MANUAL CHECK RECOMMENDED

Review the affected bnxt_en TPA descriptor path and platform DMA or IOMMU behavior to determine whether a zero DMA address can cause an actual host memory write, a deterministic kernel crash, or only a device-local DMA fault.

## 7. Call-site confidence

Call-site confidence: medium

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

Patch: bnxt_en: Propagate RX ring init failures in bnxt_init_nic()
Commit: daadccd062fdca5e77a8cc22ffe35857803b6c49
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=daadccd062fdca5e77a8cc22ffe35857803b6c49

Commit description:

bnxt_init_rx_rings() returns an error when bnxt_alloc_one_rx_ring()
fails, but bnxt_init_nic() discards that return value and calls
bnxt_init_chip(), which enables TPA.

If an allocation fails, this could leave rxr->rx_tpa[] partially zeroed
and TPA would be enabled over an array with zeroed entries. This would
lead to a zeroed DMA address being handed out if the agg_idx is
translated to a SW index at a zeroed entry.

Fix this by propagating the error out of bnxt_init_nic(). Both callers
already check its return value and unwind with bnxt_free_skbs() and
bnxt_free_mem(), which tolerate a partially initialized RX ring.

Fixes: c0c050c ("bnxt_en: New Broadcom ethernet driver.")
Reported-by: Sashiko <sashiko-bot+sashiko@kernel.org>
Link: https://netdev-ai.bots.linux.dev/sashiko/#/patchset/20260828190900.1767611-1-joe%40dama.to
Cc: stable@vger.kernel.org
Signed-off-by: Joe Damato <joe@dama.to>
Link: https://patch.msgid.link/20260902015652.2421609-6-joe@dama.to
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Changed files:
  drivers/net/ethernet/broadcom/bnxt/bnxt.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=daadccd062fdca5e77a8cc22ffe35857803b6c49

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

The original Linux kernel CVE announcement for CVE-2026-97572 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-97572

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