[CVE-2026-64003][LOW] scsi: core: Run queues for all non-SDEV_DEL devices from scsi_run_host_queues [ Upstream

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

CVE: CVE-2026-64003
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: scsi: core: Run queues for all non-SDEV_DEL devices from scsi_run_host_queues [ Upstream
Commit: 15fb19af49f2073ed77fad16aaabc648b0ca6800
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=15fb19af49f2073ed77fad16aaabc648b0ca6800
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-64003
Analysis date: Sun, 19 Jul 2026 16:27:35 -0400
ActionableScore: 2
ActionableScore lower bound: 1
Actionable bucket: Ordinary Moderate / Low-like
Manual review required: NO

Summary:
SCSI host recovery may fail to restart queues for partially removed non-SDEV_DEL devices, leaving requeued requests stuck and causing a device removal hang or local storage availability impact.

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

The original Linux kernel CVE announcement for CVE-2026-64003 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-64003

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.

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AL-KERNEL CLASSIFICATION RESULT
======================================================================

CVE-2026-64003	LOW	CHECK WITH IMPACT FROM ORIG NN LOW	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-755;CWE-667;**CWE-400;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '4.7';DESCR 'SCSI host recovery can leave requeued requests stuck because scsi_run_host_queues used an iterator that skips partially removed devices such as SDEV_CANCEL. When such a device still has requeued commands, its queue may never be kicked after recovery completes, which can hang the device removal path and cause a local availability impact. For the CVSS the PR:L is used in the paranoid score because some environments may delegate block device or storage control to a non root service or container user, although the more typical administrative case is PR:H. The issue is not directly network reachable as a packet parsing bug. It is triggered through SCSI recovery and device lifecycle operations, possibly with storage fabric or faulty device involvement. Impact is denial of service through stuck requests and a hung removal path, without evidence of memory corruption, information disclosure, or privilege escalation.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 2)	YES	LOCK DANGER HARDWARE  DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3	YES	NO	checked

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

ActionableScore=2
ActionableScoreLower=1

## 1. ActionableScore

* Conservative score: 1
* Paranoid score: 2
* Final recommended bucket: **Ordinary Moderate / Low-like**::

## 2. Signal breakdown

Conservative signals:

* Reliable kernel hang / DoS: +1. Requeued SCSI requests may never be kicked, causing device removal to hang.
* Important filesystem/storage path: +1. This is in SCSI core queue recovery/removal handling.
* Requires admin/root/storage-management privileges in typical deployments: -2. Reliable triggering usually requires device removal, recovery, reset, or storage-management control.

Conservative total: 1.

Paranoid additional interpretation:

* Firmware-mediated or storage-fabric influence: +1. A faulty or malicious device, target, or storage fabric could help create recovery/removal conditions, but this is not ordinary remote network reachability.

Paranoid total: 2.

Not counted:

* No generic memory corruption. The patch fixes iteration and reference handling, not UAF/OOB/write corruption.
* No privilege escalation signal. No attacker-controlled reclaim, overwrite, callback control, refcount takeover, or object confusion is shown.
* No confidentiality or integrity impact. The described effect is stuck requests and removal hang.
* No direct network reachability. Storage fabric involvement is at most indirect.

## 3. Reachability analysis

The bug is triggered when a SCSI host leaves recovery while a partially removed device such as SDEV_CANCEL still has requeued requests. In typical deployments, creating this state requires administrative control over storage devices, device removal, reset, or error recovery. A reduced-privilege storage service or delegated container may lower practical privileges in some environments, but this is not a normal unprivileged local-user path.

The path is in a common storage subsystem, but the vulnerable condition depends on recovery/removal timing and queued commands. It is not a packet-processing bug and is not directly reachable from the network. A remote storage target or firmware can influence reliability only if the system uses such a storage setup.

Call-site confidence: high. The changed function and its queue-running behavior are directly shown.

## 4. Severity interpretation

This behaves like an ordinary Moderate or Low-like availability issue. The realistic impact is a hung SCSI device removal path or stuck I/O recovery, not kernel memory corruption or privilege escalation. The paranoid score remains low because even with storage-fabric influence, the patch does not show a stronger exploitation primitive.

## 5. One-sentence report phrase

SCSI host recovery may fail to restart queues for partially removed non-SDEV_DEL devices, leaving requeued requests stuck and causing a device removal hang or local storage availability impact.

## 6. Manual review recommendation

NO MANUAL CHECK NEEDED.

Reason: the issue is storage availability only, requires special recovery/removal conditions, and the patch does not indicate memory corruption, security-boundary bypass, information disclosure, or privilege escalation.

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

Patch: scsi: core: Run queues for all non-SDEV_DEL devices from scsi_run_host_queues [ Upstream
Commit: 15fb19af49f2073ed77fad16aaabc648b0ca6800
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=15fb19af49f2073ed77fad16aaabc648b0ca6800

Changed files:
  drivers/scsi/scsi_lib.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=15fb19af49f2073ed77fad16aaabc648b0ca6800

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

The original Linux kernel CVE announcement for CVE-2026-64003 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-64003

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:L
  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: 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: 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).