[CVE-2026-92516][LOW] bpf: Fix offset warn check for bpf_res_spin_lock [ Upstream

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

CVE: CVE-2026-92516
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: bpf: Fix offset warn check for bpf_res_spin_lock [ Upstream
Commit: dfdce1f20a7e5e826165c556fd3367c65387e966
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=dfdce1f20a7e5e826165c556fd3367c65387e966
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-92516
Analysis date: Fri, 18 Sep 2026 08:54:26 -0400
ActionableScore: 0
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-2026-92516 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-92516

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-2026-92516	LOW	https://www.kernelcve.org/list/?q=CVE-2026-92516 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:H';CWE-617;CWE-754;CWE-670;Other CVSS 'AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:N';BEST CVSS score: '5.5';DESCR 'An incorrect offset check for BPF_RES_SPIN_LOCK can test the regular BPF_SPIN_LOCK offset instead of the resource spin lock offset. This can generate a spurious kernel warning when both lock types are present and can fail to diagnose a duplicate resource spin lock. For the CVSS the PR:L rating reflects that a local process must be able to load a crafted BPF object with the required BPF capabilities. The issue is not network reachable. No memory corruption, information disclosure, integrity impact, or privilege escalation primitive is indicated by the patch. Under a panic_on_warn configuration, the warning may cause a local kernel panic and denial of service.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 0)  SKIP CVE-2026-92516 UNKNOWN SKIP The Fixes patch not applied yet, so unlikely that actual: url YES  NO NO unknown 	MAYBE	LOCK WARNONLY BPF SIMPLEFIX IMPROVEONLY LINUS  INCREASED_FROM_LOW_BASED_ON_HIGHCVSSSCORE DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN4 DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3	-	-	checked

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

ActionableScore=0
PrimitiveClass=NONE
RealUAF=NO
HostAdminRequired=UNKNOWN
NamespaceScopedPrivilege=UNKNOWN
ImportantCandidate=NO
ManualReview=NO
AutoDowngradeAllowed=YES

1. ActionableScore

* Raw conservative score: 0
* Conservative score: 0
* Raw paranoid score: 0
* Paranoid score: 0
* Final recommended bucket: **Ordinary Moderate**::

The issue is a diagnostic logic error. The only potentially severe outcome is conditional on `panic_on_warn` and on privileged BPF object loading, which does not establish a general kernel corruption or security-boundary primitive.

2. Signal breakdown

* +0 Incorrect warning-state validation: `BPF_RES_SPIN_LOCK` checks `spin_lock_off` instead of `res_spin_lock_off`. This can emit a spurious `WARN_ON_ONCE` or fail to warn for a duplicate resource spin lock.
* +0 WARN-only behavior: the patch establishes a warning-condition bug, not a dereference, UAF, OOB access, refcount error, ownership violation, or corruption sink.
* +0 Conditional panic: `panic_on_warn` could convert a reachable warning into a host panic, but that is a non-default administrator-controlled configuration and is not an independently demonstrated fatal consequence in the supplied patch.
* -1 Privilege-gated BPF interface: reaching `btf_parse_fields()` through attacker-supplied BTF normally requires BPF loading capability. The complete capability and namespace scope are not shown, so this is treated as a reachability constraint rather than proof of host-admin-only access.

Important non-awarded signals:

* No UAF, stale reference, refcount mutation, double release, or lifetime violation is established.
* No controlled reclaim, active object replacement, arbitrary write, callback control, disclosure, or integrity primitive is established.
* No remote reachability is established.
* No local-unprivileged trigger is established because BPF loading privileges are required in normal configurations.
* No availability point is awarded for the warning itself. `WARN_ON_ONCE` is non-fatal unless `panic_on_warn` is enabled.
* No confidentiality or integrity point is awarded because the patch does not demonstrate data disclosure or unauthorized modification.
* No privilege-escalation concern is established.

3. Reachability analysis

The relevant path is reached while parsing BTF fields for BPF objects containing `BPF_RES_SPIN_LOCK`. A triggering BTF layout would need both a regular `BPF_SPIN_LOCK` and a resource spin lock, or multiple resource spin locks, in a way accepted by the BPF type-validation path.

Loading the necessary BPF object and BTF data is normally privilege-gated through BPF-related capability checks. The supplied patch does not establish whether the full sequence is reachable through delegated `CAP_BPF`, a BPF token, a container-scoped capability, or only through a host-privileged process. Therefore:

* Host-admin-equivalent privilege is not positively established.
* Below-host-admin reachability is also not positively established.
* Namespace-scoped reachability is unresolved because the complete BPF load and verifier path is not shown.
* There is no network trigger and no special hardware requirement.
* There is no race requirement.

4. Primitive and severity interpretation

The exact defect is an incorrect field-offset check in a `WARN_ON_ONCE` condition. The code validates `rec->spin_lock_off` while processing a `BPF_RES_SPIN_LOCK`, instead of validating the relevant `rec->res_spin_lock_off` field.

This is not a memory-lifetime issue and does not establish a UAF, double free, invalid pointer use, OOB access, refcount corruption, or active-state ownership violation. The demonstrated consequence is limited to incorrect diagnostic behavior. A malformed or unusual BTF layout can cause a spurious warning, while duplicate resource spin locks may not be diagnosed by this specific warning.

If the host administrator has enabled `panic_on_warn`, a warning could terminate the kernel. That remains a conditional DoS configuration consequence, not evidence of a memory-corruption primitive or privilege escalation path.

`PrimitiveClass=NONE` is appropriate because no meaningful corruption, authorization, ownership, lifetime, or security-boundary primitive is established. `ImportantCandidate=NO` and `AutoDowngradeAllowed=YES` are appropriate because the patch only fixes warning-state validation and leaves no unresolved exploit-relevant primitive.

Likely operational severity is Low-like. The issue can be handled through normal maintenance unless the deployment both enables `panic_on_warn` and delegates BPF loading privileges to untrusted users.

5. One-sentence report phrase

An incorrect BPF_RES_SPIN_LOCK offset warning check can produce a spurious kernel warning or miss duplicate resource spin lock diagnostics, with no demonstrated memory-corruption or privilege-escalation primitive.

6. Manual review recommendation

NO MANUAL CHECK NEEDED

The patch fixes a warning-condition bookkeeping error only. Manual review is unnecessary unless the product enables `panic_on_warn` and permits untrusted users to load the relevant BPF objects.

7. Call-site confidence

Call-site confidence: medium

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

Patch: bpf: Fix offset warn check for bpf_res_spin_lock [ Upstream
Commit: dfdce1f20a7e5e826165c556fd3367c65387e966
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=dfdce1f20a7e5e826165c556fd3367c65387e966

Changed files:
  kernel/bpf/btf.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=dfdce1f20a7e5e826165c556fd3367c65387e966

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

The original Linux kernel CVE announcement for CVE-2026-92516 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-92516

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:L/PR:L/UI:N/S:U/C:N/I:N/A:N
  The Best / paranoid CVSS vector: AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS score: 5.5

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: 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).