[CVE-2026-98662][MODERATE 7.0] iio: light: gp2ap020a00f: drain irq_work after free_irq

[CVE-2026-98662][MODERATE 7.0] iio: light: gp2ap020a00f: drain irq_work after free_irq

[AL-KERNEL]

CVE: CVE-2026-98662
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: YES
Patch: iio: light: gp2ap020a00f: drain irq_work after free_irq
Commit: a36814b9fe00970116d30c3143d81e7425c4d334
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=a36814b9fe00970116d30c3143d81e7425c4d334
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98662
Analysis date: Mon, 19 Oct 2026 05:43:34 -0400
ActionableScore: 4
ActionableScore lower bound: unknown
Actionable bucket: Borderline / manual review recommended
Manual review required: YES

Summary:
A teardown race in the gp2ap020a00f IIO driver can let pending irq_work poll a trigger after devm cleanup has freed it, causing a local use after free and potentially a kernel crash.

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

The original Linux kernel CVE announcement for CVE-2026-98662 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98662

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-2026-98662	MODERATE	https://www.kernelcve.org/list/?q=CVE-2026-98662 CHECK WITH IMPACT FROM ORIG NN MODERATE | 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:H/I:H/A:H';*CWE-416;CWE-362;CWE-667;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '7';DESCR 'A race in the gp2ap020a00f driver allows queued irq_work to execute after the associated IIO trigger has been released during device removal. free_irq does not drain work that the threaded IRQ handler already queued, so the delayed call to iio_trigger_poll can dereference freed trigger memory. The directly supported impact is a local kernel crash and denial of service. Because this is a confirmed use after free rather than a simple NULL pointer dereference, reuse of the freed allocation may also create a potential path to confidentiality or integrity impact and privilege escalation, although no reliable write primitive is demonstrated. For the CVSS the PR:L value in the paranoid score represents deployments where a local service, container root, or restricted device management account can initiate driver removal or unbind operations. Normal direct device removal usually requires administrative privileges and is represented by PR:H in the base score. AC:H applies because successful triggering depends on winning a race between queued irq_work and device teardown. The issue is not network reachable and normally requires the affected I2C sensor driver and device to be present. 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 Borderline / manual review recommended. The production rules then evaluated CVSS thresholds and ActionableScore thresholds. No severity changing production threshold or specialist override was recorded. 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. The independent weaker Aegis shadow evaluated CVSS 1.9 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	ERRORPATH UAF HARDWARE LINUS KPANIC 	-	-	checked

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

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

1. ActionableScore

* Raw conservative score: 2
* Conservative score: 4
* Raw paranoid score: 2
* Paranoid score: 4
* Applied conservative floor: 2 -> 4 under REAL UAF FLOOR 4.
* Applied paranoid floor: 2 -> 4 under REAL UAF FLOOR 4.
* Final recommended bucket: **Borderline / manual review recommended**::

2. Signal breakdown

* +2 Real UAF. Queued irq_work can call `iio_trigger_poll()` after devm cleanup has freed `data->trig`.
* +1 Realistic kernel crash or strong DoS. Dereferencing the released IIO trigger can cause an Oops or panic, although no crash trace is supplied.
* -1 Narrow teardown race. Work must be queued before `free_irq()` and remain pending until after remove returns and devm cleanup frees the trigger.
* No privilege penalty. Manual unbind and module removal normally involve administration, but the supplied evidence does not prove that every probe-error or remove path requires a host administrator.
* No structured stale-object leverage point. The stale trigger is an active structured object, but attacker-controlled reclaim, replacement contents, callbacks, or useful field manipulation are not established.
* No strong or weak LPE point. A generic possibility of heap reuse after a UAF is insufficient.
* No repeated release or refcount point. The stale operation is `iio_trigger_poll()`, not a second put, free, release, or refcount mutation on the same object.
* No extra availability point. The possible kernel crash is already counted.
* No confidentiality or integrity point. No disclosure, directed write, or controlled post-free corruption is demonstrated.
* Remote reachability, authorization bypass, checksum metadata corruption, B3-PENDING, B4-PENDING, and B5-R are not applicable.

3. Reachability analysis

The affected gp2ap020a00f I2C device and driver must be present. An IRQ must queue `data->work`, followed by probe failure or device removal before that work executes.

Writing to a driver unbind interface or unloading the module ordinarily requires administrative control. However, the supplied patch also fixes the probe error path, and the evidence does not establish the privilege boundary for every possible teardown source. Therefore `HostAdminRequired=UNKNOWN`, not YES or NO.

No ordinary-user, delegated service, user-namespace, or container trigger is established. The complete operation is not shown to be namespace-scoped. There is no network trigger. The race is a relatively narrow and potentially one-shot teardown ordering, and attacker-controlled repetition is not demonstrated.

4. Primitive and severity interpretation

The exact primitive is a post-lifetime dereference of a freed IIO trigger by asynchronous irq_work. This is a real UAF involving an active structured object rather than a NULL dereference or passive bookkeeping error.

The stale use performs trigger polling after teardown, but the evidence does not establish controlled reclaim, attacker-shaped replacement data, function-pointer control, arbitrary read or write, repeated lifetime mutation, or privilege escalation. The demonstrated security consequence is therefore a plausible kernel crash and local DoS. Stronger exploitation remains theoretical.

This is `CLASS_B` because a genuine kernel lifetime violation exists. It is constrained by teardown timing, specialized device presence, unresolved attacker reachability, and lack of meaningful exploitation leverage. `ImportantCandidate=NO` is appropriate. `AutoDowngradeAllowed=YES` is appropriate because no unresolved strong corruption or security-boundary primitive is established.

5. One-sentence report phrase

A teardown race in the gp2ap020a00f IIO driver can let pending irq_work poll a trigger after devm cleanup has freed it, causing a local use after free and potentially a kernel crash.

6. Manual review recommendation

MANUAL CHECK RECOMMENDED

The UAF is concrete, but current evidence supports a constrained teardown-time crash path rather than an Important-grade exploitation primitive.

7. Call-site confidence

Call-site confidence: high

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

Patch: iio: light: gp2ap020a00f: drain irq_work after free_irq
Commit: a36814b9fe00970116d30c3143d81e7425c4d334
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=a36814b9fe00970116d30c3143d81e7425c4d334

Commit description:

The threaded IRQ handler queues data->work through irq_work_queue() so
the trigger is polled from a per-CPU context.  free_irq() does not flush
an irq_work the handler already queued, so after gp2ap020a00f_remove()
returns that work may still run and call iio_trigger_poll() on data->trig,
which the devm cleanup has already freed, causing a use-after-free.

Add irq_work_sync(&data->work) after free_irq() in remove() and in the
probe error path, mirroring commit 7860172 ("iio: trigger: sysfs:
fix use-after-free on remove").

Found by an in-house static analysis tool, confirmed by manual review.

Fixes: bf29fbe ("iio: gp2ap020a00f: Add a driver for the device")
Cc: stable@vger.kernel.org
Assisted-by: Codex:gpt-5.6
Signed-off-by: Fan Wu <fanwu01@zju.edu.cn>
Signed-off-by: Jonathan Cameron <jonathan.cameron@oss.qualcomm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Changed files:
  drivers/iio/light/gp2ap020a00f.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=a36814b9fe00970116d30c3143d81e7425c4d334

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

The original Linux kernel CVE announcement for CVE-2026-98662 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98662

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: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).