[CVE-2025-71313][LOW] PCI: endpoint: Add missing NULL check for alloc_workqueue() [ Upstream

[CVE-2025-71313][LOW] PCI: endpoint: Add missing NULL check for alloc_workqueue() [ Upstream

[AL-KERNEL]

CVE: CVE-2025-71313
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: YES
Patch: PCI: endpoint: Add missing NULL check for alloc_workqueue() [ Upstream
Commit: 314eab6740bcda504ef978be599f805de05ce6de
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=314eab6740bcda504ef978be599f805de05ce6de
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2025-71313
Analysis date: Wed, 03 Jun 2026 15:08:56 -0400
ActionableScore: 0
ActionableScore lower bound: unknown
Actionable bucket: Ordinary Moderate / Low-like
Manual review required: NO

Summary:
No one-sentence report phrase was found.

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

The original Linux kernel CVE announcement for CVE-2025-71313 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2025-71313

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-2025-71313	LOW	CHECK	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-252;**CWE-476;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 'A missing NULL check after alloc_workqueue can leave the PCI endpoint NTB driver registered with a NULL kpcintb_workqueue pointer after an allocation failure. A later queue_work path may dereference that NULL workqueue pointer and crash the kernel. For the CVSS the PR:L is used in the paranoid score only for environments where a reduced capability local account or delegated endpoint management service can trigger driver initialization or endpoint configuration. In typical deployments the base score uses PR:H because PCI endpoint function setup and driver loading are administrative operations. The issue is not network reachable and there is no concrete UAF, OOB write, or arbitrary write primitive. Impact is denial of service via kernel crash only.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 0) 	MAYBE	NULLPTR NOMEMCHK SIMPLEFIX HARDWARE LINUS KPANIC 	-	-	checked

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

ActionableScore=0

1. **ActionableScore**
* Conservative score: 0
* Paranoid score: 0
* Final recommended bucket: **Ordinary Moderate / Low-like**::

2. **Signal breakdown**
* Reliable kernel crash / strong DoS: +1. A NULL workqueue pointer may later be passed to queue_work() and cause a NULL pointer dereference.
* Hard or unreliable trigger: -1. The bug requires alloc_workqueue() failure at driver initialization time, which depends on memory pressure or allocation failure timing.
* Requires admin/root/CAP-level control in typical deployments: -2. Loading or configuring PCI endpoint NTB/vNTB function drivers is normally an administrative or device-management operation.
* Rare AND difficult-to-reach subsystem/configuration: -1. PCI endpoint NTB/vNTB is not a common default user-exposed path and usually requires specific endpoint-capable hardware and configuration.
* No memory corruption signal. The primitive is a NULL pointer dereference, not UAF, OOB write, double-free, refcount corruption, or attacker-controlled overwrite.

3. **Reachability analysis**
The realistic trigger is local and privileged: driver initialization or PCI endpoint function setup must occur, and alloc_workqueue() must fail. Namespaces or containers normally do not make this reachable to unprivileged users unless a management service delegates endpoint configuration in an unusual way. The path is not network reachable and is not default-exposed on typical systems.

4. **Severity interpretation**
This behaves like a Low-like or ordinary Moderate DoS issue, not an actionable Moderate or Important-class vulnerability. The theoretical effect is a kernel crash, but the triggering condition is constrained and administrative. There is no evidence of privilege escalation, confidentiality impact, integrity impact, or a reusable memory corruption primitive.

5. **One-sentence report phrase**
A missing NULL check after alloc_workqueue() in PCI endpoint NTB/vNTB initialization can leave a NULL workqueue pointer that may later cause a local privileged kernel crash, but exploitation requires allocation failure during a rare device-management path.

6. **Manual review recommendation**
NO MANUAL CHECK NEEDED

Reason: DoS-only NULL dereference, no memory corruption primitive, no network reachability, rare subsystem, and typical trigger requires administrative PCI endpoint management.

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

Patch: PCI: endpoint: Add missing NULL check for alloc_workqueue() [ Upstream
Commit: 314eab6740bcda504ef978be599f805de05ce6de
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=314eab6740bcda504ef978be599f805de05ce6de

Changed files:
  drivers/pci/endpoint/functions/pci-epf-ntb.c
  drivers/pci/endpoint/functions/pci-epf-vntb.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=314eab6740bcda504ef978be599f805de05ce6de

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

The original Linux kernel CVE announcement for CVE-2025-71313 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2025-71313

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: 0

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: YES
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).