[CVE-2026-98494][LOW] net: atl1: fix soft lockup on out-of-range cmb_tpd_next_to_clean read

[CVE-2026-98494][LOW] net: atl1: fix soft lockup on out-of-range cmb_tpd_next_to_clean read

[AL-KERNEL]

CVE: CVE-2026-98494
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: net: atl1: fix soft lockup on out-of-range cmb_tpd_next_to_clean read
Commit: 5d7ac337d37cb97d77e4c910d37746694b606661
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=5d7ac337d37cb97d77e4c910d37746694b606661
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98494
Analysis date: Sat, 24 Oct 2026 08:11:00 -0400
ActionableScore: 1
ActionableScore lower bound: unknown
Actionable bucket: Ordinary Moderate
Manual review required: NO

Summary:
An invalid atl1 hardware TX consumer index can make interrupt cleanup spin indefinitely, causing a soft lockup without a demonstrated memory-corruption primitive.

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

The original Linux kernel CVE announcement for CVE-2026-98494 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98494

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-2026-98494	LOW	https://www.kernelcve.org/list/?q=CVE-2026-98494 CHECK WITH IMPACT FROM ORIG NN MODERATE | AEGIS IMPACT MODERATE AEGIS_AS=1 LEGACY=LOW RESULT=DIFF (final Legacy and Aegis differ; FINAL: LOW, Aegis: 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:N/I:N/A:H';*CWE-20;*CWE-835;CWE-754;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '4.7';DESCR 'The atl1 TX interrupt cleanup path can loop forever when hardware reports an invalid cmb_tpd_next_to_clean value such as 0xffff during a PCIe link or MAC reset. The software consumer index wraps only inside the valid ring range and can never equal that value, causing a CPU soft lockup and availability loss. The invalid hardware value is used as a loop target rather than directly as a buffer index, so there is no supported OOB, UAF, information leak, or write primitive. For the CVSS the PR:H base value reflects the administrative control normally needed to reset or reconfigure the device. For the CVSS the PR:L paranoid value covers delegated device management, but reliable unprivileged or remote triggering is not established. Automated impact decision path. The original SimpleNet classifier selected MODERATE_KPANIC. The primary LLM estimated paranoid CVSS 4.7 and the production ActionableScore returned 1 with recommendation Ordinary Moderate. The production rules then evaluated CVSS thresholds and ActionableScore thresholds. Recorded rule transitions were CVSS and initial triage stage MODERATE_KPANIC to MODERATE because the CVSS score, vector or bug class threshold rule was applied. ActionableScore thresholds stage MODERATE to LOW because the ActionableScore threshold rule was applied. final reconciliation stage LOW to LOW because KP specialist did not establish a qualifying panic and the cross model evidence reconciliation rule was applied. The legacy KP specialist has no review artifact for this run. The legacy FD or DH downgrade specialist has no review artifact for this run. Exact triggered rule markers were DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH and DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3 and KPANIC_UNSUPPORTED_REMOVED and V64_AEGIS_UNSUPPORTED_PROMOTION_BLOCKED. The independent weaker Aegis shadow evaluated CVSS 2.0 and ActionableScore 1 with primitive class CLASS_C and manual review REQUIRED. Its independently reconciled impact was MODERATE. The models disagreed but the aggregation rules retained the production result. The final reported impact is LOW.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 1)	MAYBE	REMOTE OOB DEADLOCK SIMPLEFIX NETWORK HARDWARE DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3 KPANIC_UNSUPPORTED_REMOVED V64_AEGIS_UNSUPPORTED_PROMOTION_BLOCKED	-	-	checked

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

ActionableScore=1
PrimitiveClass=CLASS_C
RealUAF=NO
HostAdminRequired=UNKNOWN
NamespaceScopedPrivilege=UNKNOWN
ImportantCandidate=NO
ManualReview=NO
AutoDowngradeAllowed=YES
RequiresHostUID0=UNKNOWN
AuthorizationDecisionBypass=NO
ProtectedResourceImpact=NONE
B4PendingReview=NO
B4PendingConfirmed=NO

1. ActionableScore

* Raw base score: 1.
* Conservative score: 1; no floor or cap applied.
* Raw paranoid score: 1.
* Paranoid score: 1; no technically supported stronger primitive.
* Final recommended bucket: **Ordinary Moderate**::

2. Signal breakdown

* +1 Reliable kernel soft lockup/strong DoS: hardware may report `0xffff`; because the software consumer index wraps within `tpd_ring->count`, the cleanup loop cannot reach that target and may spin forever.
* No OOB-write point: the invalid hardware value is only the loop terminator. Array access uses `sw_tpd_next_to_clean`, which remains a valid ring index.
* No UAF, arbitrary write, disclosure, authorization bypass, or protected-state corruption is shown.
* NEW52/B5-R does not apply: there is no confirmed heap OOB write, retry-accumulated index, or later consumption of corrupted structured state.
* No extra availability point: it would duplicate the same soft-lockup consequence.
* No privilege or timing penalty: administrative control and difficult attacker-controlled reset timing are suggested but not positively established.

3. Reachability analysis

The invalid value arises from device hardware during PCIe-link or MAC reset. The supplied evidence does not establish whether an attacker can induce the complete condition through ordinary traffic, delegated device management, namespace capabilities, or only host administration. No namespace-scoped trigger, remote reachability, prior setup requirement, or rare-hardware condition is proven. Accordingly, both effective privilege and attacker-controlled repeatability remain unknown.

4. Primitive and severity reading

The exact defect is an invalid hardware consumer value used as an unreachable loop target, producing nontermination. It is CLASS_C crash/DoS behavior, not an OOB access: the ring entry is selected by the bounded software index. There is no active structured-state corruption, repeated lifetime mutation, or downstream privileged consumer of corrupted state. Important-grade leverage is therefore unsupported, and automatic Moderate handling is safe.

5. One-sentence report phrase

An invalid atl1 hardware TX consumer index can make interrupt cleanup spin indefinitely, causing a soft lockup without a demonstrated memory-corruption primitive.

6. Manual review advice

NO MANUAL CHECK NEEDED

The patch and commit identify a bounded-index infinite loop with no unresolved corruption or trust-boundary primitive.

7. Call-site confidence

Call-site confidence: high

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

Patch: net: atl1: fix soft lockup on out-of-range cmb_tpd_next_to_clean read
Commit: 5d7ac337d37cb97d77e4c910d37746694b606661
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=5d7ac337d37cb97d77e4c910d37746694b606661

Commit description:

Same issue as atl1c (see the first commit in this series, "net:
atl1c: fix soft lockup on out-of-range tpd_cons read"): the hardware
can report an out-of-range cmb_tpd_next_to_clean (seen as 0xffff)
while the PCIe link/MAC is resetting. An out-of-range value can
never be reached and the loop below would spin forever. Treat it as
"nothing new to clean" instead.

Fixes: f3cc28c ("Add Attansic L1 ethernet driver.")
Cc: stable@vger.kernel.org
Signed-off-by: Gajdos Tamás <tamas@rimpianto.com>
Link: https://patch.msgid.link/20260921091334.3571525-4-tamas@rimpianto.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Changed files:
  drivers/net/ethernet/atheros/atlx/atl1.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=5d7ac337d37cb97d77e4c910d37746694b606661

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

The original Linux kernel CVE announcement for CVE-2026-98494 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98494

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:H
  The Best / paranoid CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS score: 4.7

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: unknown
  Paranoid ActionableScore: 1

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).