[CVE-2026-97430][LOW] xhci: Prevent queuing new commands if xhci is inaccessible [ Upstream

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

CVE: CVE-2026-97430
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: xhci: Prevent queuing new commands if xhci is inaccessible [ Upstream
Commit: a50948386256b24d73971b9a152fe1de808446ab
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=a50948386256b24d73971b9a152fe1de808446ab
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-97430
Analysis date: Thu, 24 Sep 2026 21:03:53 -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-2026-97430 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-97430

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-2026-97430	LOW	https://www.kernelcve.org/list/?q=CVE-2026-97430 CHECK WITH IMPACT FROM ORIG NN LOW	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:P/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H';CWE-362;*CWE-664;CWE-703;Other CVSS 'AV:P/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '4.2';DESCR 'A lifecycle race in the xHCI driver can queue a command after the host controller becomes inaccessible during suspend. The queued command may not be processed because the controller is stopped or unavailable, causing USB command timeouts, stalled USB operations, or suspend resume disruption. For the CVSS the PR:N because a physical attacker does not need an account or local code execution on the target, but must have physical access to a USB port and must hit a suspend related timing window. The issue is not network reachable. Impact is primarily denial of service affecting USB functionality or power state transitions. No memory corruption, information disclosure, integrity impact, or privilege escalation primitive is indicated by the patch.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 1)	YES	USB INIT WARNONLY SIMPLEFIX 	NO	NO	checked

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

ActionableScore=1
PrimitiveClass=NONE
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**::

The sole scored signal is a realistic device and USB operation availability failure. The patch shows that commands could be placed on the xHCI command ring while the controller is inaccessible during suspend. Such commands may not be processed and can cause USB command timeouts or suspend resume disruption. There is no supported basis to raise the score for host wide crash, memory corruption, confidentiality, integrity, or privilege escalation.

2. Signal breakdown

* +1 Availability impact realistic. A command queued after HCD_FLAG_HW_ACCESSIBLE is cleared can remain unprocessed because the xHCI controller is stopped or inaccessible. This can stall USB command processing and affect USB device operations or suspend resume behavior.

Important non-awarded signals:

* +0 Real UAF. No object is freed, released, dereferenced after lifetime end, or reused according to the supplied patch.
* +0 Memory corruption. No OOB access, invalid pointer dereference, refcount misuse, DMA write after free, or arbitrary write is established.
* +0 Reliable kernel crash. The patch adds warnings and rejects command submission with ESHUTDOWN. It does not document an Oops, panic, or host wide fatal failure.
* +0 Remote reachability. No network input path is involved.
* +0 Local unprivileged trigger. The supplied context does not establish that an ordinary local user can cause the complete sequence of xHCI command submission while suspend is in progress.
* +0 Physical attacker reachability. A connected USB device may be relevant to xHCI activity, but the patch does not establish that a physical USB device can reliably trigger the complete suspend and command queue sequence without other local system actions.
* +0 Hard race penalty. The patch concerns suspend lifecycle ordering, but the supplied context does not establish a narrow or externally uncontrollable race sufficiently concrete for a negative timing penalty.
* +0 Hardware rarity penalty. xHCI is common hardware, and no unusual or rare hardware prerequisite is established.
* +0 Confidentiality and integrity. No disclosure, unauthorized modification, authorization bypass, or cross security boundary behavior is established.

3. Reachability analysis

The affected path is in the local xHCI USB host controller suspend lifecycle. The immediate vulnerable operation is queue_command while HCD_FLAG_HW_ACCESSIBLE is cleared during suspend.

The patch does not establish the identity or privilege level of an attacker that can reliably cause both command submission and the suspend transition. A physically connected USB device may participate in activity that results in xHCI commands, but physical access alone is not shown to control system suspend timing or command ring submission. Likewise, no ordinary local user trigger is established.

HostAdminRequired is UNKNOWN because the complete trigger sequence and required power management or USB control permissions are not visible. NamespaceScopedPrivilege is UNKNOWN because no namespace scoped capability checks or complete namespace reachable operation are shown. No prior privileged setup, boot parameter, unusual configuration, or special hardware beyond an xHCI controller is established.

The issue is not network reachable. It is not a firmware compromise issue. The evidence supports a local hardware lifecycle and suspend ordering defect.

4. Primitive and severity interpretation

The exact primitive is an invalid xHCI controller lifecycle state. A new command can be queued after the host controller is marked inaccessible and after suspend has begun. The likely consequence is that the command remains pending or times out because the controller cannot process it.

This is neither active structured object lifetime corruption nor fixed stale storage. No object is freed and later accessed. No concrete repeated release, put, free, or refcount mutation exists. There is no distinction between an ordinary stale cleanup dereference and a second lifetime mutation because neither occurs.

PrimitiveClass is NONE. The demonstrated and patch supported consequence is limited to USB command processing failure, device operation disruption, or suspend resume disruption. A host kernel crash is not established. Privilege escalation, controlled kernel corruption, arbitrary read or write, and information disclosure are speculative and unsupported.

ImportantCandidate is NO because there is no Class A or Class B primitive requiring exploitation leverage analysis. AutoDowngradeAllowed is YES because the patch represents a lifecycle validation and command rejection fix without an unresolved corruption or security boundary primitive. Likely operational severity is Low to ordinary Moderate depending on whether affected USB functionality is operationally important.

5. One-sentence report phrase

An xHCI suspend lifecycle issue can queue commands after the controller becomes inaccessible, potentially causing USB command timeouts or suspend resume disruption without evidence of memory corruption or privilege escalation.

6. Manual review recommendation

NO MANUAL CHECK NEEDED

The supplied patch establishes a command queue state validation issue with device and USB availability impact only. It does not establish a UAF, corruption primitive, security boundary bypass, host crash, or below host admin exploitation path.

7. Call-site confidence

Call-site confidence: medium

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

Patch: xhci: Prevent queuing new commands if xhci is inaccessible [ Upstream
Commit: a50948386256b24d73971b9a152fe1de808446ab
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=a50948386256b24d73971b9a152fe1de808446ab

Changed files:
  drivers/usb/host/xhci-ring.c
  drivers/usb/host/xhci.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=a50948386256b24d73971b9a152fe1de808446ab

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

The original Linux kernel CVE announcement for CVE-2026-97430 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-97430

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:P/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
  The Best / paranoid CVSS vector: AV:P/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS score: 4.2

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).