[CVE-2026-98676][MODERATE REGULAR] iio: adc: ade9000: fix NULL pointer dereference in clkout registration

[CVE-2026-98676][MODERATE REGULAR] iio: adc: ade9000: fix NULL pointer dereference in clkout registration

[AL-KERNEL]

CVE: CVE-2026-98676
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: iio: adc: ade9000: fix NULL pointer dereference in clkout registration
Commit: d2400175228fbc10b29c49a7b5f70a7e80d144dd
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=d2400175228fbc10b29c49a7b5f70a7e80d144dd
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98676
Analysis date: Mon, 19 Oct 2026 00:34:55 -0400
ActionableScore: 0
ActionableScore lower bound: unknown
Actionable bucket: Ordinary Moderate
Manual review required: NO

Summary:
ADE9000 clock provider registration can dereference a NULL register address during device probe and crash the kernel, but the path requires specific hardware and host-controlled external clock configuration and exposes no memory corruption or privilege-escalation primitive.

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

The original Linux kernel CVE announcement for CVE-2026-98676 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98676

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: MODERATE REGULAR
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
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CVE-2026-98676	MODERATE	https://www.kernelcve.org/list/?q=CVE-2026-98676 CHECK WITH IMPACT FROM ORIG NN MODERATE | AEGIS IMPACT MODERATE_KPANIC AEGIS_AS=0 LEGACY=MODERATE RESULT=DIFF V39_AEGIS_ONE_STEP_UP=LOW->MODERATE TEMP_DISTANCE_MERGE_SKIP=AEGIS_LOW_ELIGIBLE_NO_POSITIVE_SIGNAL (final Legacy and Aegis differ; FINAL: MODERATE, Aegis: MODERATE_KPANIC)	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-476;CWE-628;Other CVSS 'AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '5.5';DESCR 'A NULL pointer dereference occurs during ADE9000 device probe because ade9000_setup_clkout() registers CLKOUT as a divider clock with a NULL register address. The common clock framework can call clk_divider_recalc_rate() during registration and read the missing address through readl(), causing a kernel Oops or panic when the device uses an external input clock and is configured as a clock provider. The issue is not network reachable and requires the affected ADE9000 hardware together with the relevant firmware or Device Tree configuration. For the CVSS the PR:L value is used only for the paranoid score because a restricted service or delegated device manager could trigger driver reprobe in some specialized environments. Normal systems require administrative control and are better represented by PR:H. Impact is denial of service through a kernel crash. No UAF, OOB access, information disclosure, or write primitive is supported by the affected code path. Automated impact decision path. The original SimpleNet classifier selected MODERATE_KPANIC. The primary LLM estimated paranoid CVSS 5.5 and the production ActionableScore returned 0 with recommendation Ordinary Moderate. The production rules then evaluated CVSS thresholds and ActionableScore thresholds. Recorded rule transitions were CVSS and initial triage stage MODERATE_KPANIC to MODERATE because the CVSS score, vector or bug class threshold rule was applied. ActionableScore thresholds stage MODERATE to LOW because the ActionableScore threshold rule was applied. final reconciliation stage LOW to MODERATE because the cross model evidence reconciliation rule was applied. The legacy KP specialist has no review artifact for this run. The legacy FD or DH downgrade specialist has no review artifact for this run. Exact triggered rule markers were DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH and DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3 and V39_AEGIS_ONE_STEP_UP and MANUAL_REVIEW_REQUIRED. The independent weaker Aegis shadow evaluated CVSS 4.5 and ActionableScore 0 with primitive class CLASS_C and manual review NO. Its independently reconciled impact was MODERATE_KPANIC. Cross model aggregation changed the production result under an enabled evidence gated merge rule. The final reported impact is MODERATE.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 0)	MAYBE	OOB DANGER NULLPTR INIT SIMPLEFIX KERNEL_PANIC_PLUS_UAF HARDWARE LINUS DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3 V39_AEGIS_ONE_STEP_UP MANUAL_REVIEW_REQUIRED	-	-	checked

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ACTIONABLESCORE ANALYSIS
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ActionableScore=0
PrimitiveClass=CLASS_C
RealUAF=NO
HostAdminRequired=YES
NamespaceScopedPrivilege=NO
ImportantCandidate=NO
ManualReview=NO
AutoDowngradeAllowed=YES
RequiresHostUID0=UNKNOWN
AuthorizationDecisionBypass=NO
ProtectedResourceImpact=NONE
B4PendingReview=NO
B4PendingConfirmed=NO

1. ActionableScore

* Raw conservative score: -1
* Conservative score: 0
* Raw paranoid score: -1
* Paranoid score: 0
* Applied score-range normalization: -1 -> 0
* Final recommended bucket: **Ordinary Moderate**::

The paranoid analysis remains identical because delegated device reprobe is only hypothetical. The supplied evidence establishes no below-host-admin trigger.

2. Signal breakdown

Positive signals:

* +1 Reliable kernel crash. Registering the divider invokes `clk_divider_recalc_rate()`, which passes a NULL register address to `readl()` and crashes during probe.
* +0 CLASS_C invalid dereference. The operation is a read from NULL, not a demonstrated write or lifetime violation.

Negative signals:

* -2 Full host-admin-equivalent prerequisite. Intentional triggering requires provisioning the ADE9000 through firmware or Device Tree as a clock provider with external CLKIN, or administratively reproving the device.
* No separate rare-hardware penalty was applied because that would substantially duplicate the configuration and reachability restriction.

Not awarded:

* No UAF, OOB read, OOB write, refcount mutation, controlled reclaim, arbitrary write, active-state corruption, or security-boundary bypass.
* No confidentiality or integrity signal.
* No remote, namespace-scoped, or ordinary local-user reachability.
* No additional availability point because it would duplicate the same probe-time crash.
* NEW52 B5-R does not apply because there is no heap OOB write, accumulated retry index, or later consumption of corrupted structured state.
* NEW53 B3-PENDING does not apply because no shared-backing write exists.
* V33 and V34 do not apply because no attacker-influenced active structured state is written.
* B4-PENDING does not apply because no authorization decision or mandatory security guard is involved.

3. Reachability analysis

The failure requires an ADE9000 configured as a clock provider with an external input clock. The vulnerable operation runs during driver probe and crashes deterministically once that platform configuration exists.

An ordinary user cannot normally create the firmware or Device Tree description, instantiate the SPI device, or request driver unbind and reprobe. These operations are not user-namespace or network-namespace scoped. A hypothetical delegated device-management service is not established by the supplied evidence and is therefore not used for scoring.

The external clock configuration and supported physical device are prerequisites. The internal-clock configuration is unaffected because it does not register this clock provider. No race or retry sequence is involved.

4. Primitive and severity interpretation

The exact primitive is a NULL MMIO-style read through `readl(NULL)` during clock registration. This is neither active structured corruption nor stale storage. It is a deterministic initialization-time invalid dereference classified as CLASS_C.

The demonstrated consequence is a kernel Oops or panic during device probe. There is no patch-supported mechanism for modifying kernel memory, leaking data, changing authorization state, or escalating privileges. ImportantCandidate is NO because no independently useful primitive remains after excluding the crash. AutoDowngradeAllowed is YES because the defect is a hardware-specific, host-admin-configured crash with no unresolved corruption or trust-boundary mechanism.

5. One-sentence report phrase

ADE9000 clock provider registration can dereference a NULL register address during device probe and crash the kernel, but the path requires specific hardware and host-controlled external clock configuration and exposes no memory corruption or privilege-escalation primitive.

6. Manual review recommendation

NO MANUAL CHECK NEEDED

The established behavior is limited to a deterministic probe-time NULL dereference under host-admin-controlled hardware configuration.

7. Call-site confidence

Call-site confidence: high

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

Patch: iio: adc: ade9000: fix NULL pointer dereference in clkout registration
Commit: d2400175228fbc10b29c49a7b5f70a7e80d144dd
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=d2400175228fbc10b29c49a7b5f70a7e80d144dd

Commit description:

ade9000_setup_clkout() passes NULL as the register address when
registering a divider clock. During clock registration, the common
clock framework calls clk_divider_recalc_rate(), which dereferences
the address through readl(). As a result, probing an ADE9000 configured
as a clock provider with an external input clock crashes.

CLKOUT passes CLKIN through without changing its rate. Register it as
a 1:1 fixed-factor clock, which does not require register access.

This change does not affect the configuration using the internal clock,
for which the driver does not register a clock provider.

Fixes: 81de7b4 ("iio: adc: add ade9000 support")
Cc: stable@vger.kernel.org
Signed-off-by: Linmao Li <lilinmao@kylinos.cn>
Reviewed-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
Signed-off-by: Jonathan Cameron <jonathan.cameron@oss.qualcomm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Changed files:
  drivers/iio/adc/ade9000.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=d2400175228fbc10b29c49a7b5f70a7e80d144dd

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

The original Linux kernel CVE announcement for CVE-2026-98676 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98676

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:H/UI:N/S:U/C:N/I:N/A:H
  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: MODERATE
KPANIC detected for this report: NO
Published priority for this report (same as in Subject): MODERATE REGULAR

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).