* [CVE-2026-97571][MODERATE REGULAR] bnxt_en: Propagate TPA buffer allocation failures in bnxt_queue_mem_alloc()
@ 2026-09-25 12:45 21% AL-KERNEL
0 siblings, 0 replies; 1+ results
From: AL-KERNEL @ 2026-09-25 12:45 UTC (permalink / raw)
To: kernel-cve
CVE: CVE-2026-97571
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: bnxt_en: Propagate TPA buffer allocation failures in bnxt_queue_mem_alloc()
Commit: c8050386a2209b2a474c1eb4bd1574dc19129bfb
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=c8050386a2209b2a474c1eb4bd1574dc19129bfb
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-97571
Analysis date: Fri, 25 Sep 2026 08:45:08 -0400
ActionableScore: 2
ActionableScore lower bound: 1
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-2026-97571 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-97571
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.
======================================================================
AL-KERNEL CLASSIFICATION RESULT
======================================================================
CVE-2026-97571 MODERATE https://www.kernelcve.org/list/?q=CVE-2026-97571 CHECK WITH IMPACT FROM ORIG NN MODERATE Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:A/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H';CWE-252;CWE-665;*CWE-787;Other CVSS 'AV:A/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '7.1';DESCR 'An unchecked TPA buffer allocation failure can leave a bnxt receive ring partially initialized while allowing the ring to be started. A hardware selected aggregation identifier can then select an uninitialized rx_tpa entry and provide a zero DMA address to the NIC. Incoming traffic that exercises TPA may cause a DMA operation using that invalid address. For the CVSS the PR:L is used for the paranoid score because a constrained service account container root or delegated network administrator may be able to participate in interface setup and resource pressure conditions without full host administration. The confirmed impact is at least denial of service through a DMA or IOMMU fault. On systems without effective IOMMU isolation the zero DMA address creates a plausible memory corruption concern with possible confidentiality and integrity impact. YES REQUIRES MANUAL CHECK';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 2) YES REMOTE OOB INIT SIMPLEFIX NETWORK SKB DMAorINTERRUPT HARDWARE DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN4 YES NO checked
======================================================================
ACTIONABLESCORE ANALYSIS
======================================================================
ActionableScore=2
ActionableScoreLower=1
PrimitiveClass=CLASS_B
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**::
2. Signal breakdown
Conservative signals:
* +1 Constrained kernel corruption candidate. The patch establishes that a partially initialized TPA receive ring can be started and an uninitialized `rxr->rx_tpa[]` slot can supply DMA address zero to the NIC. This is a fixed and highly constrained DMA target, not attacker-selected kernel memory.
* +0 Reliable kernel crash or host-wide DoS not awarded. The patch does not demonstrate a panic, IOMMU fault, machine check, or host crash.
* +0 Confidentiality and integrity impact not awarded. There is no demonstrated arbitrary or directed DMA target, controlled replacement, disclosure, or protected-state overwrite.
* +0 Direct remote reachability not awarded. Incoming traffic may exercise the already-invalid ring, but the supplied evidence does not show that a remote attacker can also reliably cause the required TPA allocation failure and ring startup.
* +0 Privilege penalty not applied. The complete operation that creates the failed allocation state is not shown to require host-admin privilege, but below-host-admin reachability is also not established.
Paranoid-only signal:
* +1 Firmware-mediated external influence. After the invalid ring state exists, NIC hardware selects the aggregation identifier and receives traffic through the affected RX path. This is not scored as direct remote reachability because local allocation failure and device setup remain prerequisites.
No double-counting was applied. The possible DMA fault or device malfunction was not counted as both corruption and a separate reliable availability impact.
3. Reachability analysis
The vulnerable state requires `bnxt_alloc_one_tpa_info_data()` to fail with `ENOMEM` during TPA ring setup while `bnxt_queue_mem_alloc()` previously ignored the failure and permitted `bnxt_queue_start()` to install the partially initialized ring.
The supplied patch does not establish who can reliably cause this setup sequence. It may involve interface initialization, reset, channel reconfiguration, driver reload, or other device lifecycle operations. Such operations can require administrative network or driver-management privileges in many deployments, but the exact capability checks and namespace scope are not visible here.
A network peer may send traffic after the malformed ring has been installed, and that traffic can cause the NIC to process aggregation state. However, the same remote peer is not shown to control the preceding allocation failure or ring setup. Therefore, direct remote reachability is not established.
No namespace-scoped complete trigger chain is demonstrated. There is no supplied evidence that an attacker can create a namespace, obtain the necessary scoped capability, induce the allocation failure, start the affected physical or virtual BNXT device, and send triggering traffic without host-level cooperation.
No rare-hardware penalty was applied. The issue is driver-specific and requires BNXT hardware with TPA enabled, but driver specificity alone does not prove physical-only or unusually inaccessible exploitation.
4. Primitive and severity interpretation
The exact primitive is an unchecked allocation failure that leaves entries of the active TPA receive-ring metadata zeroed. A hardware-selected aggregation identifier can select one of these entries, resulting in a zero DMA address being provided to the NIC.
This is not a UAF, stale-object bug, repeated release, refcount mutation, double free, or ownership-lifetime violation. There is no first lifetime operation, surviving dangling reference, or second lifetime-affecting operation.
The possible DMA write is constrained because the destination is fixed at zero rather than selected by the attacker. The patch does not establish that the NIC successfully writes attacker-controlled data to physical address zero, that address zero is accessible without IOMMU translation, or that this produces a controllable overwrite rather than a DMA fault, device error, dropped packet, or device reset.
PrimitiveClass is CLASS_B because a potentially security-relevant invalid DMA operation is concretely implied by the receive-ring state, but exploitation leverage is unresolved. It is not CLASS_A because there is no attacker-directed write, controlled DMA target, controlled active-object corruption, arbitrary kernel read or write, callback influence, or demonstrated privilege escalation.
ImportantCandidate is NO because the demonstrated primitive is fixed-target and hardware-dependent, with no established useful post-corruption action beyond possible device or host failure. AutoDowngradeAllowed is YES because the available evidence supports a constrained DMA-invalid-state issue rather than unresolved active-object lifetime corruption or a security-boundary bypass.
Operationally, this should be treated as an ordinary Moderate-class driver reliability and possible DMA-safety issue. It warrants verification on affected BNXT hardware and IOMMU configurations, but the supplied evidence does not support Important severity.
5. One-sentence report phrase
An unchecked TPA allocation failure can start a partially initialized BNXT receive ring and provide a zero DMA address to the NIC, creating a constrained potential DMA fault or corruption condition that requires hardware-specific manual validation.
6. Manual review recommendation
MANUAL CHECK RECOMMENDED
Verify whether affected BNXT hardware can issue a receive DMA transaction using the zero address, whether the IOMMU blocks that transaction, and whether an unprivileged or delegated actor can reliably create the failed allocation and ring-start sequence.
7. Call-site confidence
Call-site confidence: medium
======================================================================
UPSTREAM PATCH SUMMARY
======================================================================
Patch: bnxt_en: Propagate TPA buffer allocation failures in bnxt_queue_mem_alloc()
Commit: c8050386a2209b2a474c1eb4bd1574dc19129bfb
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=c8050386a2209b2a474c1eb4bd1574dc19129bfb
Commit description:
bnxt_alloc_one_tpa_info_data() returns -ENOMEM as soon as one allocation
fails. This leaves the remaining rxr->rx_tpa[] entries zeroed.
bnxt_queue_mem_alloc() discards that return value, so the partially
initialized ring is installed by bnxt_queue_start().
Since the agg_id is picked by the hardware and bnxt_alloc_agg_idx maps
it to a SW index in rxr->rx_tpa[], it is possible that an uninitialized
slot can be chosen which would hand a zero DMA address to the device.
Fix this by checking the return value of bnxt_alloc_one_tpa_info_data
and unwinding, freeing the ring buffers.
Fixes: bd649c5 ("bnxt_en: handle tpa_info in queue API implementation")
Reported-by: Sashiko <[email protected]>
Link: https://netdev-ai.bots.linux.dev/sashiko/#/patchset/20260828190900.1767611-1-joe%40dama.to
Cc: [email protected]
Signed-off-by: Joe Damato <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Paolo Abeni <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
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=c8050386a2209b2a474c1eb4bd1574dc19129bfb
======================================================================
DETAILED REPORT METHODOLOGY
======================================================================
The original Linux kernel CVE announcement for CVE-2026-97571 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-97571
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:A/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H
The Best / paranoid CVSS vector: AV:A/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
The Best / paranoid CVSS score: 7.1
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: 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 [email protected] (and both
send reply to CVE record itself too and see "reply" button below for howto reply).
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