[CVE-2026-98915][MODERATE 7.0] media: video-i2c: use vb2_video_unregister_device on driver removal [ Upstream

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

CVE: CVE-2026-98915
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: YES
Patch: media: video-i2c: use vb2_video_unregister_device on driver removal [ Upstream
Commit: 97adc8cd04df2085f7fd437838005f3bb16bafae
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=97adc8cd04df2085f7fd437838005f3bb16bafae
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98915
Analysis date: Mon, 26 Oct 2026 20:43:04 -0400
ActionableScore: 3
ActionableScore lower bound: unknown
Actionable bucket: Borderline / manual review recommended
Manual review required: YES

Summary:
Using the generic unregister helper can leave a VB2 queue active during driver removal, allowing operations on an existing local FD to consume stale device state and potentially crash the kernel.

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ABOUT THIS REPORT
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The original Linux kernel CVE announcement for CVE-2026-98915 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98915

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-2026-98915	MODERATE	https://www.kernelcve.org/list/?q=CVE-2026-98915 CHECK WITH IMPACT FROM ORIG NN LOW | AEGIS IMPACT MODERATE_KPANIC AEGIS_AS=0 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-672;*CWE-416;CWE-362;*CWE-664;Other CVSS 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '7';DESCR 'The video i2c driver used video_unregister_device even though open file handles are released through vb2_fop_release. This can leave the vb2 queue insufficiently disconnected while driver removal proceeds, so an existing local file descriptor may access stale queue or device state and cause a kernel crash. A use after free path is plausible if queue containing driver memory is released before the final file operation, but this diff does not establish an arbitrary read or write primitive. For the CVSS the PR:L value is selected because an attacker needs local access to the video device node, while concurrent device removal or driver unbind is treated as an external race precondition. The issue is not directly network reachable and AC:H reflects the required lifetime window during removal. Automated impact decision path. The original SimpleNet classifier selected LOW. The primary LLM estimated paranoid CVSS 7 and the production ActionableScore returned 3 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. ActionableScore thresholds stage MODERATE_KPANIC to MODERATE because the ActionableScore threshold rule was applied. final reconciliation stage MODERATE to MODERATE_KPANIC 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 INCREASED_FROM_LOW_BASED_ON_REQUIREMANUALCHECK and DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN4 and V39_AEGIS_ONE_STEP_UP and MANUAL_REVIEW_REQUIRED. The independent weaker Aegis shadow evaluated CVSS 0.0 and ActionableScore 0 with primitive class NONE 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 Borderline / manual review recommended (with actual score 3)	MAYBE	USB INIT HARDWARE LINUS  INCREASED_FROM_LOW_BASED_ON_REQUIREMANUALCHECK DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN4 KPANIC V39_AEGIS_ONE_STEP_UP MANUAL_REVIEW_REQUIRED	-	-	checked

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

ActionableScore=3
PrimitiveClass=CLASS_B
RealUAF=NO
HostAdminRequired=NO
NamespaceScopedPrivilege=UNKNOWN
ImportantCandidate=NO
ManualReview=RECOMMENDED
AutoDowngradeAllowed=YES
RequiresHostUID0=NO
AuthorizationDecisionBypass=NO
ProtectedResourceImpact=NONE
B4PendingReview=NO
B4PendingConfirmed=NO

1. ActionableScore

* Raw base score: 3.
* Conservative score: 3; no floor or cap applied.
* Raw paranoid score: 3.
* Paranoid score: 3; a possible UAF is not scored without a demonstrated post-free access.
* Final recommended bucket: **Borderline / manual review recommended**::

2. Signal breakdown

* +1 weak/indirect lifetime-state corruption: `video_unregister_device()` omits the VB2 queue disconnection required by `vb2_fop_release()`, leaving active structured queue state available during removal.
* +1 reliable kernel-crash concern: an existing file operation may consume inadequately disconnected queue/device state after removal begins.
* +1 local below-host-admin trigger: the supplied evidence identifies a local actor with an already-open video-device FD; removal remains an external precondition.
* No timing penalty: concurrent removal is required, but the evidence does not establish a narrow or inherently unreliable race.
* No Real UAF +2: freeing of the queue or containing driver allocation before a specific later dereference is not visible.
* No structured-UAF leverage, controlled reclaim, arbitrary write, disclosure, integrity impact, or LPE is shown.
* No extra availability point: it would duplicate the same possible crash.

3. Reachability analysis

The grounded actor is a local process with access to the video device node and an existing FD. Driver removal or unbind is a separate external lifecycle event; the attacker is not shown to control it. The supplied PR:L assessment supports below-host-admin FD use, but no namespace-capability path is established. No network path, special hardware rarity, or attacker-controlled repeatable removal sequence is proven.

4. Primitive and severity reading

The patch restores an active-state retirement protocol: the VB2 queue must be disconnected before video-device unregistration because later release operations use VB2 semantics. This supports CLASS_B lifecycle/structured-state risk, but not a confirmed UAF: the exact free and post-free consumer are absent. The shown practical concern is stale queue consumption and kernel crash; post-free corruption is speculative. With no material reuse or trust-boundary primitive, this is not an Important candidate and may be downgraded after review.

5. One-sentence report phrase

Using the generic unregister helper can leave a VB2 queue active during driver removal, allowing operations on an existing local FD to consume stale device state and potentially crash the kernel.

6. Manual review advice

MANUAL CHECK RECOMMENDED

Confirm the driver-data lifetime, final-FD release path, and whether any ioctl or queue operation dereferences freed storage after removal.

7. Call-site confidence

Call-site confidence: medium

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

Patch: media: video-i2c: use vb2_video_unregister_device on driver removal [ Upstream
Commit: 97adc8cd04df2085f7fd437838005f3bb16bafae
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=97adc8cd04df2085f7fd437838005f3bb16bafae

Changed files:
  drivers/media/i2c/video-i2c.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=97adc8cd04df2085f7fd437838005f3bb16bafae

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

The original Linux kernel CVE announcement for CVE-2026-98915 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98915

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: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: 3

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).