[CVE-2026-98128][LOW] scsi: mpi3mr: Fix target device refcount leak in mpi3mr_sas_port_add() [ Upstream

[CVE-2026-98128][LOW] scsi: mpi3mr: Fix target device refcount leak in mpi3mr_sas_port_add() [ Upstream

[AL-KERNEL]

CVE: CVE-2026-98128
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: scsi: mpi3mr: Fix target device refcount leak in mpi3mr_sas_port_add() [ Upstream
Commit: 040146f81d099006a354b0caacc7f01ca00f257e
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=040146f81d099006a354b0caacc7f01ca00f257e
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98128
Analysis date: Fri, 25 Sep 2026 07:17:51 -0400
ActionableScore: 2
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-2026-98128 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98128

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-2026-98128	LOW	https://www.kernelcve.org/list/?q=CVE-2026-98128 CHECK WITH IMPACT FROM ORIG NN LOW	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H';*CWE-401;*CWE-772;**CWE-400;Other CVSS 'AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '5.3';DESCR 'A reference leak in the mpi3mr SAS transport path occurs because mpi3mr_sas_port_add can acquire a target device reference and then reach an error path without calling mpi3mr_tgtdev_put. The leaked kref prevents the target device structure from being freed and repeated discovery or port creation failures may gradually consume kernel memory. For the CVSS the PR:N value is used because a potentially malicious or faulty SAS device does not require local credentials on the host, although practical triggering requires access to an attached SAS storage environment. The attack vector is adjacent rather than network reachable. Impact is limited to resource exhaustion and denial of service. 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 2)	YES	SIMPLEFIX LEAK HARDWARE LINUS  INCREASED_FROM_LOW_BASED_ON_HIGHCVSSSCORE DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN4 DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3	NO	NO	checked

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

ActionableScore=2
PrimitiveClass=NONE
RealUAF=NO
HostAdminRequired=NO
NamespaceScopedPrivilege=NO
ImportantCandidate=NO
ManualReview=NO
AutoDowngradeAllowed=YES

1. ActionableScore

* Raw conservative score: 2
* Conservative score: 2
* Raw paranoid score: 2
* Paranoid score: 2
* Final recommended bucket: **Ordinary Moderate**::

2. Signal breakdown

* +1 Concrete persistent kernel resource/reference leak. `mpi3mr_get_tgtdev_by_addr()` acquires a target-device kref, and the visible `out_fail` cleanup path did not call `mpi3mr_tgtdev_put()`. The acquired reference may remain permanently held and prevent target-device destruction.
* +1 Firmware-mediated external influence. The affected path handles SAS target-device and port discovery. An attached SAS device or SAS topology event can plausibly participate in reaching the discovery failure path without requiring local host credentials.
* +0 No real UAF. The patch fixes a missing `put()` after a successful `get()`. It does not show a release followed by a stale dereference, second release, double free, or refcount mutation through freed storage.
* +0 Controlled reclaim is not demonstrated.
* +0 Arbitrary or directed kernel write is not demonstrated.
* +0 Confidentiality and integrity impact are not demonstrated.
* +0 Strong DoS is not demonstrated. The patch proves a persistent reference leak, but does not demonstrate that a single operation or a small number of operations causes host-wide memory exhaustion.
* +0 Remote network reachability is not established. SAS-attached-device influence is adjacent or device-mediated, not direct network reachability.
* +0 No host-admin penalty applied. The supplied scenario permits an attached malicious or faulty SAS device to influence discovery without local host credentials.
* +0 No rare-hardware penalty applied. `mpi3mr` is hardware-specific, but the supplied evidence does not establish that the required SAS controller or attached SAS device is exceptionally rare enough to justify a scoring penalty.

3. Reachability analysis

The relevant attacker model is an adjacent attacker controlling, emulating, or causing fault conditions in an attached SAS target device or SAS topology. The target-device reference is acquired during SAS port discovery and is leaked only when a later operation follows the `out_fail` path.

Host-admin-equivalent privilege is not required for the device-originated trigger model. The attacker needs access to the SAS storage environment, controller attachment path, or a device capable of provoking repeated discovery or port-add failures. This is not a direct network attack path.

No namespace-scoped privilege model is relevant. The vulnerable operation is performed by the host SCSI driver while processing controller and SAS-device discovery state. The patch does not establish that an ordinary local user, a container user, or a namespaced capability can independently instantiate and repeatedly drive the complete vulnerable operation.

Repeated triggering is plausible only if the attacker can repeatedly induce the relevant discovery or error condition. The patch establishes the leak on each qualifying failure path, but does not establish an easy or reliable high-frequency trigger.

4. Primitive and severity interpretation

The exact primitive is a missing reference release. A target-device kref is incremented, then an error path frees the partially created SAS-port object without dropping the target-device reference. The target-device object can therefore remain retained after it should normally become freeable.

This is neither active stale-object use nor fixed stale storage. It is a resource ownership and reference-lifetime leak. There is no first release that may free the object followed by a second release through a dangling reference. Therefore, the concrete repeated release/refcount rule does not apply.

PrimitiveClass is NONE because no meaningful corruption, post-free access, authorization bypass, semantic reinterpretation, or active-object lifetime violation is established. The demonstrated consequence is retained kernel memory and target-device state. The speculative consequence is gradual resource exhaustion after repeated qualifying discovery failures.

ImportantCandidate is NO because the patch does not establish memory corruption, a security boundary bypass, cross-tenant resource isolation failure, or meaningful exploitation leverage beyond resource consumption. AutoDowngradeAllowed is YES because this is a concrete but constrained reference leak without unresolved post-free mutation or corruption primitive.

Likely operational severity is Low to ordinary Moderate. Systems that use MPI3MR controllers and repeatedly attach, remove, or rediscover faulty SAS devices may experience accumulated kernel memory usage. Immediate kernel compromise, privilege escalation, information disclosure, or host crash is not supported by the patch.

5. One-sentence report phrase

A missing target-device reference release in the mpi3mr SAS port error path can retain target-device objects after repeated discovery failures and may cause gradual kernel resource exhaustion, but no memory-corruption or privilege-escalation primitive is established.

6. Manual review recommendation

NO MANUAL CHECK NEEDED

The patch establishes a missing `put()` reference cleanup and a persistent resource leak only. It does not establish UAF, double release, stale-object access, arbitrary write, security-boundary bypass, or a demonstrated host-wide denial-of-service condition.

7. Call-site confidence

Call-site confidence: medium

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

Patch: scsi: mpi3mr: Fix target device refcount leak in mpi3mr_sas_port_add() [ Upstream
Commit: 040146f81d099006a354b0caacc7f01ca00f257e
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=040146f81d099006a354b0caacc7f01ca00f257e

Changed files:
  drivers/scsi/mpi3mr/mpi3mr_transport.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=040146f81d099006a354b0caacc7f01ca00f257e

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

The original Linux kernel CVE announcement for CVE-2026-98128 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98128

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:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
  The Best / paranoid CVSS vector: AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS score: 5.3

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: 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).