[CVE-2026-98657][MODERATE 7.0] iio: proximity: pulsedlight: fix iio_device left registered on PM setup failure

[CVE-2026-98657][MODERATE 7.0] iio: proximity: pulsedlight: fix iio_device left registered on PM setup failure

[AL-KERNEL]

CVE: CVE-2026-98657
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: YES
Patch: iio: proximity: pulsedlight: fix iio_device left registered on PM setup failure
Commit: 06fa13c53442257b94ea1519555ceddaaea57e0d
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=06fa13c53442257b94ea1519555ceddaaea57e0d
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98657
Analysis date: Sat, 24 Oct 2026 12:07:00 -0400
ActionableScore: 4
ActionableScore lower bound: unknown
Actionable bucket: Actionable Moderate / Strong Important candidate requiring manual review
Manual review required: YES

Summary:
A probe failure leaves a freed IIO device registered behind live sysfs/chardev interfaces, creating a concrete local active-object UAF with plausible kernel crash and unresolved reuse leverage.

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

The original Linux kernel CVE announcement for CVE-2026-98657 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98657

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.

======================================================================
AL-KERNEL CLASSIFICATION RESULT
======================================================================

CVE-2026-98657	MODERATE	https://www.kernelcve.org/list/?q=CVE-2026-98657 CHECK WITH IMPACT FROM ORIG NN MODERATE | AEGIS IMPACT MODERATE_KPANIC AEGIS_AS=4 LEGACY=MODERATE_KPANIC RESULT=SAME V39_AEGIS_ONE_STEP_UP=MODERATE->MODERATE_KPANIC (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:H/I:H/A:H';*CWE-416;CWE-459;*CWE-672;Other CVSS 'AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:H';BEST CVSS score: '7';DESCR 'A probe error after successful iio_device_register can leave the IIO device registered while its devm managed indio_dev memory is released. The remaining sysfs or character device nodes can then reference freed kernel memory, creating a concrete local use after free with possible kernel crash and potentially stronger impact if the freed allocation is reused. For the CVSS the PR:L value reflects that exploitation requires a local process able to access a remaining IIO interface. AC:H reflects the additional requirement that pm_runtime_set_active must first fail during probe, and ordinary unprivileged users may not be able to force this prerequisite reliably. Automated impact decision path. The original SimpleNet classifier selected MODERATE_KPANIC. The primary LLM estimated paranoid CVSS 7 and the production ActionableScore returned 4 with recommendation Actionable Moderate / Strong Important candidate requiring manual review. The production rules then evaluated CVSS thresholds and ActionableScore thresholds. Recorded rule transitions were KP and FD specialist checks stage MODERATE_KPANIC to MODERATE because KP specialist did not establish a qualifying panic. final reconciliation stage MODERATE to MODERATE_KPANIC because the cross model evidence reconciliation rule 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 DECREASED_TO_MODERATEREG_BASED_ON_FALSEPOSCHECKOFKP and V39_AEGIS_ONE_STEP_UP and MANUAL_REVIEW_REQUIRED. The independent weaker Aegis shadow evaluated CVSS 2.5 and ActionableScore 4 with primitive class CLASS_B and manual review REQUIRED. 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_KPANIC.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Actionable Moderate / Strong Important candidate requiring manual review (with actual score 4)	MAYBE	INIT UAF HARDWARE LINUS  DECREASED_TO_MODERATEREG_BASED_ON_FALSEPOSCHECKOFKP KPANIC V39_AEGIS_ONE_STEP_UP MANUAL_REVIEW_REQUIRED	-	-	checked

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

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

1. ActionableScore

* Raw base score: 3.
* Conservative score: 4. REAL UAF FLOOR 4 applies because a freed, still-registered structured object remains available to later consumers and host-admin-only reachability is not proven.
* Raw paranoid score: 3.
* Paranoid score: 4. No additional exploit primitive is sufficiently supported.
* Final recommended bucket: **Actionable Moderate / Strong Important candidate requiring manual review**::

2. Signal breakdown

* +2 — Real UAF: `iio_device_register()` succeeds, probe subsequently returns an error without unregistering, and devm frees `indio_dev` while IIO registrations still reference it.
* +1 — Plausible kernel crash/strong DoS when a surviving sysfs or character-device operation dereferences the freed object.
* +0 — No race penalty: this is an ordered probe-error path, not evidence of difficult timing.
* +0 — No privilege penalty: neither host-admin-only triggering nor below-host-admin complete reachability is established.
* Floor 4 applied; no cap applied.
* Not awarded: controlled reclaim, attacker-shaped replacement contents, arbitrary write, disclosure, integrity impact, callback control, or LPE.
* No repeated release/refcount operation is shown; FLOOR 5 and repeated-refcount paranoid leverage do not apply.
* No authorization decision changes from DENY to ALLOW, so B4-PENDING does not apply.

3. Reachability analysis

The prerequisite is failure of `pm_runtime_set_active()` during probe. The patch does not show that a local attacker can induce this failure, bind the I2C device, or otherwise drive the complete setup. Once failure occurs, stale sysfs/chardev nodes remain, but their precise permissions and availability to an ordinary user are not supplied. Thus host-admin and namespace privilege requirements remain unknown. No race is required, and no unusual-hardware penalty is justified solely because this is an IIO driver.

4. Primitive and severity reading

This is an active structured-object UAF, not fixed stale storage: the freed `iio_dev` remains published through live IIO interfaces and can be consumed by later kernel operations. It is broader than a cleanup-only stale dereference, but the supplied diff does not expose the exact stale fields consumed or demonstrate controlled reuse. The primitive is therefore CLASS_B. ImportantCandidate is YES because an externally registered active kernel object escapes its lifetime and subsequent exploit leverage is materially unresolved. Auto-downgrade is disallowed pending review of node permissions, consumers, and reclaim behavior.

5. One-sentence report phrase

A probe failure leaves a freed IIO device registered behind live sysfs/chardev interfaces, creating a concrete local active-object UAF with plausible kernel crash and unresolved reuse leverage.

6. Manual review advice

MANUAL CHECK REQUIRED

Review the complete probe-failure reachability, stale-node permissions, subsequent IIO consumers, and whether reclaim can influence fields used by those consumers.

7. Call-site confidence

Call-site confidence: medium

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

Patch: iio: proximity: pulsedlight: fix iio_device left registered on PM setup failure
Commit: 06fa13c53442257b94ea1519555ceddaaea57e0d
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=06fa13c53442257b94ea1519555ceddaaea57e0d

Commit description:

pm_runtime_set_active() failing in probe() jumps to error_unreg_buffer,
which only calls iio_triggered_buffer_cleanup() -- it does not undo the
iio_device_register() that already succeeded a few lines above. probe()
then returns the error, the devm-managed indio_dev is freed, but the
iio core still has it registered: the sysfs/chardev nodes stay live and
point at freed memory.

Add an error_unreg_dev label that unregisters the iio device before
falling through to the existing buffer cleanup, mirroring the teardown
order already used in lidar_remove().

Fixes: 4ac4e08 ("iio: pulsedlight-lidar-lite: add runtime PM")
Assisted-by: Claude:claude-opus-4
Signed-off-by: Cong Nguyen <congnt264@gmail.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/proximity/pulsedlight-lidar-lite-v2.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=06fa13c53442257b94ea1519555ceddaaea57e0d

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

The original Linux kernel CVE announcement for CVE-2026-98657 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98657

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:L/UI:N/S:U/C:L/I:L/A:H
  The Best / paranoid CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
  The Best / paranoid CVSS score: 7

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).