[CVE-2026-97483][LOW] usb: core: hcd: fix possible deadlock in rh control transfers [ Upstream

[CVE-2026-97483][LOW] usb: core: hcd: fix possible deadlock in rh control transfers [ Upstream

[AL-KERNEL]

CVE: CVE-2026-97483
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: usb: core: hcd: fix possible deadlock in rh control transfers [ Upstream
Commit: fff917c85d37a294397c5440a795591ca9d6b602
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=fff917c85d37a294397c5440a795591ca9d6b602
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-97483
Analysis date: Thu, 24 Sep 2026 20:06:42 -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-2026-97483 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-97483

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-2026-97483	LOW	https://www.kernelcve.org/list/?q=CVE-2026-97483 CHECK WITH IMPACT FROM ORIG NN MODERATE	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-833;CWE-667;**CWE-400;BEST CVSS score: '4.2';DESCR 'A deadlock can occur during SCSI error recovery for a UAS USB storage device because root hub control transfer handling allocates memory with GFP_KERNEL even when the caller passes IO restricted allocation flags. A device reset may require resume and control transfers to the root hub. Memory reclaim from the SCSI error handler can then initiate IO and deadlock the recovery path. For the CVSS the PR:N because an attacker controlling a physically connected USB device does not need privileges on the target system. The attack vector is physical and requires a specific UAS error and reset sequence. Impact is denial of service through stalled storage recovery or blocked IO. No 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	DEADLOCK USB SIMPLEFIX HARDWARE LINUS  DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3	NO	NO	checked

======================================================================
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**::

No floor or cap was applied.

2. Signal breakdown

* +1 Reliable kernel availability impact. The patch establishes a possible deadlock in the SCSI error recovery path when root hub control transfer allocation uses GFP_KERNEL and may recursively trigger IO. A deadlock can stall recovery and block storage IO.
* No UAF, stale reference, double release, refcount mutation, OOB access, invalid free, arbitrary write, or active-object lifetime violation is established.
* No controlled reclaim, object replacement, attacker-controlled post-free data, callback influence, information disclosure, integrity impact, authorization bypass, or LPE primitive is demonstrated.
* No remote reachability bonus. The affected path depends on a local USB UAS storage topology and SCSI error recovery, not network traffic.
* No firmware-mediated attacker-control bonus. The supplied patch shows device error handling but does not establish that an attacker-controlled USB device can reliably induce the required error and reset sequence.
* No hardware penalty. USB UAS storage is not inherently rare hardware, although physical device access and a specific recovery sequence are material practical prerequisites.
* No hard-race penalty. The issue is an allocation-context deadlock, not a timing race.
* No separate Availability point. The potential blocked IO and deadlock are the same consequence already counted by the strong DoS signal.

3. Reachability analysis

The direct affected path is USB UAS storage error recovery. A reset of a UAS device can require resume operations and root hub control transfers. The root hub path previously allocated memory using GFP_KERNEL instead of preserving the caller allocation flags such as GFP_NOIO.

The patch does not establish a complete attacker-controlled trigger chain. A malicious or malfunctioning physically connected USB UAS device may be relevant, but the supplied evidence does not prove that an attacker can reliably force the required SCSI error, reset, memory-reclaim condition, and deadlock without additional host configuration or workload conditions.

Host-admin-equivalent privilege is not positively established as required, but below-host-admin attacker reachability is also not positively established for the complete trigger. Therefore HostAdminRequired is UNKNOWN. No namespace-scoped capability or namespace-local trigger is involved. NamespaceScopedPrivilege is UNKNOWN.

4. Primitive and severity interpretation

The exact defect is an allocation-context violation. Root hub control transfers execute synchronously, but rh_call_control allocated a temporary descriptor buffer with GFP_KERNEL even when usb_hcd_submit_urb received restrictive allocation flags. During SCSI error handling, GFP_KERNEL allocation may enter reclaim and initiate IO, recursively interacting with the storage recovery path and causing deadlock.

This is neither active structured-object corruption nor fixed stale storage. There is no UAF, refcount misuse, second release, cleanup-time stale dereference, memory overwrite, or semantic security-boundary bypass. The demonstrated consequence is a possible storage recovery deadlock and resulting denial of service.

The primitive is classified as NONE because the patch establishes a deadlock condition but no meaningful corruption, lifetime, ownership, authorization, or disclosure primitive. ImportantCandidate is NO because no unresolved exploitation leverage beyond availability impact exists. AutoDowngradeAllowed is YES because the issue is a constrained DoS-only defect without a demonstrated kernel-corruption or security-boundary primitive.

5. One-sentence report phrase

A root hub control transfer could allocate memory with GFP_KERNEL during UAS SCSI error recovery despite IO restricted caller flags, potentially causing recursive IO and a storage recovery deadlock.

6. Manual review recommendation

NO MANUAL CHECK NEEDED

The supplied patch supports a constrained deadlock and storage IO denial of service scenario only. No memory-corruption, privilege-escalation, confidentiality, integrity, or security-boundary primitive is established.

7. Call-site confidence

Call-site confidence: medium

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

Patch: usb: core: hcd: fix possible deadlock in rh control transfers [ Upstream
Commit: fff917c85d37a294397c5440a795591ca9d6b602
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=fff917c85d37a294397c5440a795591ca9d6b602

Changed files:
  drivers/usb/core/hcd.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=fff917c85d37a294397c5440a795591ca9d6b602

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

The original Linux kernel CVE announcement for CVE-2026-97483 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-97483

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: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).