[CVE-2026-97477][LOW] RDMA/counter: Fix num_counters leak on bind_qp failure in alloc_and_bind() [ Upstream

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

CVE: CVE-2026-97477
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: RDMA/counter: Fix num_counters leak on bind_qp failure in alloc_and_bind() [ Upstream
Commit: da95cb016812c0e012ea839f191926e35ca8f57f
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=da95cb016812c0e012ea839f191926e35ca8f57f
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-97477
Analysis date: Thu, 24 Sep 2026 20:36:33 -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-2026-97477 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-97477

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-2026-97477	LOW	https://www.kernelcve.org/list/?q=CVE-2026-97477 CHECK WITH IMPACT FROM ORIG NN LOW	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L';*CWE-772;*CWE-664;**CWE-400;BEST CVSS score: '3.3';DESCR 'A logic error in RDMA counter allocation can leave port_counter num_counters incremented when __rdma_counter_bind_qp fails. The stale counter value can keep the affected RDMA port in MANUAL mode, prevent switching to AUTO mode with EBUSY, and prevent the expected MANUAL to NONE automatic revert. For the CVSS the PR:L value is used because a local process needs access to the RDMA device and the relevant QP management interface. The issue is not directly network reachable because ordinary RDMA traffic does not execute this local control plane error path. Impact is limited availability degradation of RDMA counter mode management for the affected port. No memory corruption, information disclosure, or privilege escalation primitive is indicated by the patch.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 1)	YES	LOCK SIMPLEFIX LEAK ERRORPATH NETWORK 	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**::

2. Signal breakdown

* +1 Concrete persistent logical accounting leak. A failed __rdma_counter_bind_qp call leaves port_counter num_counters incremented even though the newly allocated counter is freed and never becomes bound. The stale count persists across repeated failures and can prevent counter mode changes for the affected RDMA port.
* +0 No memory corruption. The counter object is released on the error path and the patch does not indicate a stale pointer, UAF, double free, invalid dereference, OOB access, or refcount operation on freed storage.
* +0 No reliable host wide crash or strong DoS is established. The demonstrated effect is persistent incorrect RDMA counter mode state and EBUSY for AUTO mode selection on one port.
* +0 No confidentiality or integrity impact is established. The incorrect value is control plane accounting state, not an attacker controlled write to protected memory or data.
* +0 No remote reachability. Ordinary RDMA network traffic does not directly invoke alloc_and_bind or the failing local QP counter binding path.
* +0 No local unprivileged trigger bonus. The supplied patch does not establish which uverbs or device permissions are sufficient to create the relevant QP and reach this exact counter binding failure path below host administration.
* No privilege penalty is applied. Host administrator requirement is unresolved rather than positively established.
* No rare hardware or subsystem penalty is applied. RDMA is specialized, but the supplied evidence does not establish that an attacker cannot reach an exposed RDMA device.

3. Reachability analysis

The vulnerable path is local RDMA control plane handling during QP counter allocation and binding. Triggering requires access to an RDMA device and the ability to perform operations that reach alloc_and_bind and cause __rdma_counter_bind_qp to fail.

The patch does not show the complete uverbs call path, device permission checks, or whether the relevant counter operation is available to an ordinary user, a delegated RDMA service account, a namespace scoped capability holder, or only a host administrator. Therefore HostAdminRequired and NamespaceScopedPrivilege are UNKNOWN.

No network packet path is shown. A remote RDMA peer cannot directly trigger this bug merely by sending RDMA traffic. There is no special hardware exploit condition beyond the presence of an RDMA device, and no timing race is involved.

4. Primitive and severity interpretation

The primitive is a persistent logical counter and mode state leak. The failed bind path increments port_counter num_counters but previously skipped the matching decrement and MANUAL to NONE mode restoration.

This is not an active structured object UAF, fixed stale storage issue, double release, or repeated lifetime mutation. The counter object itself is freed after the failure, while the leaked state is the port level accounting value and counter mode. No later operation dereferences or mutates freed counter storage.

The demonstrated consequence is limited availability degradation of RDMA counter management for the affected port. Repeated failures can retain MANUAL mode and prevent a switch to AUTO mode. A broader host DoS, privilege escalation, data disclosure, protected state modification, or memory corruption mechanism is not supported by the patch.

PrimitiveClass is NONE. ImportantCandidate is NO because no kernel corruption, authorization bypass, cross boundary effect, or unresolved lifetime primitive exists. AutoDowngradeAllowed is YES because this is a bounded control plane accounting defect without a meaningful unresolved exploitation primitive.

5. One-sentence report phrase

A failed RDMA QP counter bind can leak port counter accounting state and leave the affected port in MANUAL mode, preventing expected counter mode transitions without establishing memory corruption or privilege escalation.

6. Manual review recommendation

NO MANUAL CHECK NEEDED

The patch establishes a persistent logical accounting leak with limited RDMA counter management impact, but does not establish memory corruption, a security boundary bypass, remote reachability, or meaningful privilege escalation leverage.

7. Call-site confidence

Call-site confidence: medium

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

Patch: RDMA/counter: Fix num_counters leak on bind_qp failure in alloc_and_bind() [ Upstream
Commit: da95cb016812c0e012ea839f191926e35ca8f57f
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=da95cb016812c0e012ea839f191926e35ca8f57f

Changed files:
  drivers/infiniband/core/counters.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=da95cb016812c0e012ea839f191926e35ca8f57f

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

The original Linux kernel CVE announcement for CVE-2026-97477 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-97477

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:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
  The Best / paranoid CVSS score: 3.3

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: 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).