[CVE-2026-97441][LOW] ata: ahci: fail probe if BAR too small for claimed ports [ Upstream

[CVE-2026-97441][LOW] ata: ahci: fail probe if BAR too small for claimed ports [ Upstream

[AL-KERNEL]

CVE: CVE-2026-97441
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: ata: ahci: fail probe if BAR too small for claimed ports [ Upstream
Commit: df262c828b616450eb351349e91c63447551bd01
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=df262c828b616450eb351349e91c63447551bd01
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-97441
Analysis date: Thu, 24 Sep 2026 19:04:07 -0400
ActionableScore: 1
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-2026-97441 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-97441

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-2026-97441	LOW	https://www.kernelcve.org/list/?q=CVE-2026-97441 CHECK WITH IMPACT FROM ORIG NN MODERATE	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H';*CWE-20;CWE-1284;CWE-248;BEST CVSS score: '4.6';DESCR 'An AHCI driver probe can panic the kernel when a disabled or malformed PCI controller reports a false HOST_CAP port count that requires MMIO accesses beyond the mapped BAR size. A physical attacker could potentially trigger this with a malicious or malformed AHCI compatible PCI device. For the CVSS the PR:N is used because the physical device can be presented without an existing account on the target. The issue is not network reachable. Impact is denial of service through a kernel panic. No memory corruption or privilege escalation primitive is demonstrated by the patch. NO MANUAL CHECK REQUIRED COULD BE AUTOCLOSED.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 1)	YES	DANGER HARDWARE LINUS  DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN4 DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3	NO	NO	checked

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

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

1. ActionableScore

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

No floor or cap was applied. The conservative and paranoid scores are identical because the patch establishes a kernel panic caused by invalid MMIO access, but does not establish a memory-corruption, lifetime, authorization, or ownership primitive.

2. Signal breakdown

* +1 Reliable kernel crash / strong DoS. The commit explicitly states that accessing AHCI port registers beyond the mapped PCI BAR boundary causes a kernel panic.
* +0 Invalid-state or bounds-validation failure. The controller reports an inconsistent HOST_CAP port count relative to its BAR size, but the supplied evidence does not show an attacker-controlled overwrite, arbitrary read, disclosure, or active-object corruption.
* +0 Remote reachability not established. The affected path is PCI AHCI driver probe and MMIO register access, not a network packet-processing path.
* +0 Local unprivileged trigger not established. The input does not demonstrate that an ordinary local user can introduce a malformed controller or force the relevant AHCI probe sequence.
* +0 Firmware-mediated external influence not awarded. A disabled BIOS controller can expose the bad value accidentally. A malicious PCI device is only a plausible physical scenario and is not a demonstrated complete attacker path.
* +0 Confidentiality and integrity impact not awarded. The patch demonstrates an MMIO access beyond BAR bounds followed by panic, not a disclosure, ordinary RAM out-of-bounds access, arbitrary write, or privilege escalation primitive.
* +0 Extra Availability point not awarded. The kernel panic is already counted by the single reliable crash signal.
* No negative hardware penalty was applied. AHCI hardware is broadly deployed, and the patch does not establish that rare hardware is required. Physical attacker reachability remains possible but unproven as a complete trigger model.

3. Reachability analysis

The directly established failure mode is an AHCI driver probe against a controller whose HOST_CAP register claims more ports than fit in the mapped BAR. This may occur on an existing controller disabled in BIOS and does not inherently require an attacker.

A physical attacker might plausibly present a malformed AHCI compatible PCI or PCIe device that exposes an inconsistent BAR and HOST_CAP value. However, the supplied evidence does not establish that such a device is automatically accepted, bound to the AHCI driver, and probeable on every affected deployment. It also does not establish a local software-only way for an unprivileged user to alter PCI BAR sizing or HOST_CAP contents.

HostAdminRequired is UNKNOWN. Host administration may be needed to rescan, bind, rebind, or otherwise control a PCI driver in some scenarios. Conversely, a boot-time or hotplug probe may occur without a local account once malformed hardware is present. The complete attacker sequence is not resolved.

NamespaceScopedPrivilege is UNKNOWN. No namespace-aware interface is involved in the supplied path. A network namespace, user namespace, or delegated capability does not provide control over physical PCI BAR resources or AHCI controller register values.

No prior host-side setup is established beyond the presence of an affected AHCI controller or potentially malformed physical device. There is no demonstrated race condition, repeatable lifetime transition, sysctl prerequisite, or boot parameter prerequisite.

4. Primitive and severity interpretation

The exact primitive is an invalid MMIO register access caused by trusting a malformed or bogus AHCI HOST_CAP port count without confirming that the PCI BAR contains register space for all claimed ports.

This is neither an active structured-object lifetime issue nor fixed stale storage. There is no UAF, RCU violation, double release, refcount mutation, stale pointer use, ownership violation, security-boundary bypass, or semantic reinterpretation of attacker-controlled kernel objects.

The demonstrated consequence is a kernel panic and denial of service during AHCI driver probe. The speculative consequence is a physical-device-triggered host crash if an attacker can introduce a suitable malformed PCI device. The patch does not support a stronger speculation such as arbitrary kernel memory access, controlled MMIO targeting, controlled DMA, confidentiality impact, integrity impact, or privilege escalation.

PrimitiveClass is CLASS_C because the demonstrated behavior is invalid-state processing with crash or DoS consequences only. ImportantCandidate is NO because no meaningful exploitation leverage beyond the panic is established. AutoDowngradeAllowed is YES because no unresolved corruption or security-boundary primitive would be discarded by ordinary Moderate or Low-like handling.

Likely operational severity is low. Systems with affected hardware should apply the fix through normal kernel maintenance, but the issue does not warrant urgent security escalation absent additional evidence of attacker-controlled PCI device insertion or a broader hardware-management attack path.

5. One-sentence report phrase

An AHCI controller that reports more ports in HOST_CAP than fit in its mapped PCI BAR can cause out of range MMIO register access and a kernel panic during driver probe, resulting in denial of service without a demonstrated memory-corruption or privilege-escalation primitive.

6. Manual review recommendation

NO MANUAL CHECK NEEDED

The patch establishes a BAR-size validation omission leading to a panic only. No UAF, arbitrary read or write, controlled corruption, authorization bypass, or below-host-admin software trigger is demonstrated.

7. Call-site confidence

Call-site confidence: medium

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

Patch: ata: ahci: fail probe if BAR too small for claimed ports [ Upstream
Commit: df262c828b616450eb351349e91c63447551bd01
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=df262c828b616450eb351349e91c63447551bd01

Changed files:
  drivers/ata/ahci.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=df262c828b616450eb351349e91c63447551bd01

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

The original Linux kernel CVE announcement for CVE-2026-97441 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-97441

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: Not available
  The Best / paranoid CVSS vector: AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS score: 4.6

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).