[CVE-2026-98663][MODERATE 7.0] iio: imu: adis16480: fix unprotected debugfs reads

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

CVE: CVE-2026-98663
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: YES
Patch: iio: imu: adis16480: fix unprotected debugfs reads
Commit: b7e507c6da8875da93b4130c8185e82a9dfd565c
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=b7e507c6da8875da93b4130c8185e82a9dfd565c
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98663
Analysis date: Mon, 19 Oct 2026 02:39:30 -0400
ActionableScore: 4
ActionableScore lower bound: unknown
Actionable bucket: Borderline / manual review recommended
Manual review required: YES

Summary:
A debugfs read can race with ADIS16480 device unbind and continue using a freed iio_dev, creating a local use after free with a likely kernel crash impact but no demonstrated controlled reclaim, write primitive, or privilege escalation path.

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ABOUT THIS REPORT
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The original Linux kernel CVE announcement for CVE-2026-98663 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98663

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 7.0
Manual review required: YES

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-2026-98663	MODERATE	https://www.kernelcve.org/list/?q=CVE-2026-98663 CHECK WITH IMPACT FROM ORIG NN LOW | AEGIS IMPACT MODERATE_KPANIC AEGIS_AS=0 LEGACY=MODERATE_KPANIC RESULT=SAME (final reconciliation agrees; DECISION: both MODERATE_KPANIC)	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:H';*CWE-416;CWE-362;CWE-367;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '5.8';DESCR 'The adis16480 driver creates firmware_revision and firmware_date through debugfs_create_file_unsafe even though their open coded file operations do not call debugfs_file_get. A read can therefore remain active while debugfs_remove_recursive completes during device unbind and frees the underlying iio_dev, leaving the read handler with a stale object and causing a use after free. The most direct impact is a local kernel crash or denial of service. For the CVSS the PR:L value in the paranoid score covers deployments where debugfs access is delegated to a service account, container root, or another reduced capability context while unbind or device removal occurs concurrently. The base case normally requires privileged debugfs access and device lifecycle control. The issue is not network reachable. The race requires a narrow timing window, so AC:H is appropriate. Limited confidentiality or integrity impact is considered only for the paranoid score because freed memory may be reused, but no reliable arbitrary write primitive is established. Automated impact decision path. The original SimpleNet classifier selected LOW. The primary LLM estimated paranoid CVSS 5.8 and the production ActionableScore returned 4 with recommendation Borderline / manual review recommended. The production rules then evaluated CVSS thresholds and ActionableScore thresholds. Recorded rule transitions were CVSS and initial triage stage LOW to MODERATE_KPANIC because the manual review requirement was applied. The legacy KP specialist produced a review artifact and its decision was processed by the applicable KP rules. The legacy FD or DH downgrade specialist has no review artifact for this run. Exact triggered rule markers were INCREASED_FROM_LOW_BASED_ON_REQUIREMANUALCHECK. The independent weaker Aegis shadow evaluated CVSS 4.1 and ActionableScore 0 with primitive class CLASS_B and manual review REQUIRED. Its independently reconciled impact was MODERATE_KPANIC. The shadow agreed with the final production impact and aggregation did not change that impact. The final reported impact is MODERATE_KPANIC.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline / manual review recommended (with actual score 4)	MAYBE	WARNONLY SIMPLEFIX DEBUGFS  KPANIC INCREASED_FROM_LOW_BASED_ON_REQUIREMANUALCHECK	-	-	checked

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ACTIONABLESCORE ANALYSIS
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ActionableScore=4
PrimitiveClass=CLASS_B
RealUAF=YES
HostAdminRequired=UNKNOWN
NamespaceScopedPrivilege=NO
ImportantCandidate=NO
ManualReview=RECOMMENDED
AutoDowngradeAllowed=YES
RequiresHostUID0=YES
AuthorizationDecisionBypass=NO
ProtectedResourceImpact=NONE
B4PendingReview=NO
B4PendingConfirmed=NO

## 1. ActionableScore

* Raw conservative score: 3
* Conservative score: 4
* Raw paranoid score: 3
* Paranoid score: 4
* Applied conservative floor: 3 -> 4 under REAL UAF FLOOR 4 because a stale active object is actually used and host-admin-equivalent privilege for the complete trigger is not conclusively established.
* Applied paranoid floor: 3 -> 4 for the same reason.
* Final recommended bucket: **Borderline / manual review recommended**::

## 2. Signal breakdown

Positive signals:

* +2 Real UAF. `debugfs_remove_recursive()` can complete without waiting for an active unsafe debugfs read, after which unbind frees `iio_dev` while the read callback continues using it.
* +1 Realistic kernel crash or DoS. Continuing firmware register access through the freed IIO device or its private driver state can cause an invalid dereference or kernel fault.

Negative signals:

* No negative points. The issue is a race, but the supplied evidence does not establish that the timing is sufficiently narrow or uncontrollable to justify the hard-race penalty.
* No host-admin penalty because the complete attacker model is unresolved. Mode `0400` establishes a host-UID-0 reader, but it does not by itself prove effective host-administrator capabilities, and the actor controlling unbind or physical removal may be different.

Important non-awarded signals:

* Controlled reclaim or attacker-controlled replacement contents are not demonstrated.
* No arbitrary or directed write is established.
* Structured stale-object leverage is not awarded. The callback uses an active structured object, but meaningful attacker influence over its reclaimed contents or fields is not shown.
* Attacker-influenced lifetime manipulation is not awarded because one below-host-admin principal is not shown to control both the read and device teardown.
* No additional availability point is awarded for the same possible kernel crash.
* Confidentiality, integrity, privilege escalation, and remote reachability are not established.
* There is no repeated release or refcount mutation. The stale operation is a read-side device operation rather than a second `put`, `free`, or refcount decrement.
* NEW52 B5-R, NEW53 B3-PENDING, V32, V33, and V34 do not apply. There is no established OOB write, shared-backing write, checksum metadata corruption, or cross-boundary active-state overwrite.
* Authorization B4-PENDING does not apply because no DENY-to-ALLOW authorization decision is changed.

## 3. Reachability analysis

The vulnerable files are debugfs entries with mode `0400`, so ordinary users cannot normally read them. A host UID 0 process can read them even if it has dropped broad administrative capabilities, which is why `RequiresHostUID0=YES` does not automatically imply `HostAdminRequired=YES`.

The complete trigger also requires concurrent unbind or device removal. Administrative unbind normally requires host device-management authority, while physical hot removal may be controlled by a different actor. The evidence does not establish that one reduced-privilege principal can perform the complete sequence, so `HostAdminRequired=UNKNOWN`.

The interface and physical IIO device are not user-namespace scoped. No network trigger exists. Prerequisites include `CONFIG_DEBUG_FS`, an attached ADIS16480 device, readable debugfs, and concurrent teardown. Repeated bind and unbind may make the race reproducible for an administrator, but below-host-admin repeatability is not established.

## 4. Primitive and severity interpretation

The exact primitive is a read-side use-after-free of `iio_dev` or associated driver-private state. This is an active structured object rather than a passive fixed byte buffer, and the stale callback may continue into register-access logic after teardown.

However, the evidence only supports an ordinary stale use during device removal. It does not show controlled slab reuse, attacker-shaped replacement data, callback redirection, a post-free write, repeated refcount mutation, disclosure, or an authorization boundary bypass. It is therefore `CLASS_B`, but constrained to a crash-capable lifetime defect rather than an Important-preserving exploitation primitive.

The demonstrated mechanism supports local DoS. Privilege escalation remains generic UAF speculation rather than a patch-supported consequence. `ImportantCandidate=NO` and `AutoDowngradeAllowed=YES` are appropriate because no meaningful exploitation leverage beyond the stale read and possible crash remains established.

## 5. One-sentence report phrase

A debugfs read can race with ADIS16480 device unbind and continue using a freed iio_dev, creating a local use after free with a likely kernel crash impact but no demonstrated controlled reclaim, write primitive, or privilege escalation path.

## 6. Manual review recommendation

MANUAL CHECK RECOMMENDED

The UAF is concrete and should be verified against the complete read callbacks and teardown path, but current evidence supports a constrained local crash scenario rather than mandatory Important-class preservation.

## 7. Call-site confidence

Call-site confidence: medium

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

Patch: iio: imu: adis16480: fix unprotected debugfs reads
Commit: b7e507c6da8875da93b4130c8185e82a9dfd565c
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=b7e507c6da8875da93b4130c8185e82a9dfd565c

Commit description:

The firmware_revision and firmware_date file operations are open coded
and never call debugfs_file_get(), which debugfs_create_file_unsafe()
requires. debugfs_remove_recursive() therefore does not wait for a read
in progress, and unbind frees the iio_dev underneath it.

Use debugfs_create_file() instead.

Fixes: 9bf94f8 ("imu:adis16480: fix debugfs_simple_attr.cocci warnings")
Signed-off-by: Arka Mondal <arkamondalofficial@gmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Jonathan Cameron <jonathan.cameron@oss.qualcomm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Changed files:
  drivers/iio/imu/adis16480.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=b7e507c6da8875da93b4130c8185e82a9dfd565c

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

The original Linux kernel CVE announcement for CVE-2026-98663 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98663

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:L/I:L/A:H
  The Best / paranoid CVSS score: 5.8

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: 4

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: YES
Published priority for this report (same as in Subject): MODERATE 7.0

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).