[CVE-2026-68384][MODERATE 7.0] drm/xe/vf: Fix VF CCS attach/detach race with in-flight BO moves [ Upstream

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

CVE: CVE-2026-68384
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: drm/xe/vf: Fix VF CCS attach/detach race with in-flight BO moves [ Upstream
Commit: 35ba43b541117bfb595e4b807ba447cf4335cc7d
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=35ba43b541117bfb595e4b807ba447cf4335cc7d
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68384
Analysis date: Mon, 10 Aug 2026 10:20:41 -0400
ActionableScore: 5
ActionableScore lower bound: 3
Actionable bucket: Actionable Moderate at minimum
Manual review required: YES

Summary:
A race in drm xe VF CCS attach and detach handling can leave VF migration observing partially copied or missing CCS metadata during in-flight BO moves, causing VF state corruption or denial of service with limited confidentiality and integrity concerns in the paranoid interpretation.

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ABOUT THIS REPORT
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The original Linux kernel CVE announcement for CVE-2026-68384 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68384

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-2026-68384	MODERATE	CHECK WITH IMPACT FROM ORIG NN LOW	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-362;CWE-667;CWE-703;Other CVSS 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:L';BEST CVSS score: '5.8';DESCR 'A race in drm xe VF CCS handling can occur when CCS read/write batch buffers are attached after a BO move job is prepared or detached before the in flight copy fence has completed. During VF migration this can expose a partially copied CCS metadata state or remove the attach state needed by the save/restore path while the blit is still running. For the CVSS the PR:L is used because triggering requires a local process or guest workload with access to the GPU VF rather than host administrator privileges. The issue is not directly network reachable and depends on SR-IOV VF CCS migration activity. Impact is primarily denial of service or data integrity loss for the VF workload. In the paranoid score limited confidentiality and integrity impact is kept because incorrect CCS metadata save/restore could plausibly affect migrated GPU data, but the patch does not support host memory corruption or a direct privilege escalation claim.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Actionable Moderate at minimum (with actual score 4)  SKIP CVE-2026-68384 UNKNOWN SKIP The Fixes patch not applied yet, so unlikely that actual: 864690cf4dd62482b6dd049d82c509886c904303 YES  NO NO unknown 	MAYBE	WRITE OOB INIT RACE HARDWARE MEMORY  DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN5	-	-	checked

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ACTIONABLESCORE ANALYSIS
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ActionableScore=5
ActionableScoreLower=3

## 1. ActionableScore

* Conservative score: **3**
* Paranoid score: **5**
* Final recommended bucket: **Actionable Moderate at minimum**::

## 2. Signal breakdown

Conservative signals:

* Local unprivileged or reduced-privilege trigger: **+1**
  A guest workload or local process with access to the Intel Xe SR-IOV VF GPU path may indirectly trigger BO moves during VF operation. This does not look like a full host-root-only path.
* Weak/indirect corruption candidate: **+1**
  The race can expose partially copied CCS metadata or remove CCS BB state while an in-flight blit still depends on it. This is device/GPU metadata state corruption, not proven kernel memory corruption.
* Reliable device/VF DoS or workload disruption: **+1**
  Incorrect CCS save/restore state during VF migration can plausibly break the VF workload, migration, or GPU state.
* Integrity impact plausible: **+1**
  Incorrect CCS metadata handling can corrupt migrated GPU data or make restored VF state inconsistent.
* Privileged device-management state corruption path: **+1**
  The bug is in SR-IOV VF migration and BO move handling, a trusted device-management path.
* Hard race / timing dependency: **-1**
  Exploitation depends on racing VF migration with in-flight BO moves.
* Rare / configuration-dependent exposure: **-1**
  The issue requires Intel Xe SR-IOV VF CCS support and VF migration activity, not a broad default kernel path.

Conservative total: **3**

Paranoid additions:

* Confidentiality impact plausible: **+1**
  Incorrect save/restore of CCS metadata during migration could plausibly expose or mix GPU data state across migration boundaries, although no direct host memory disclosure primitive is shown.
* Availability impact beyond immediate workload failure: **+1**
  In a virtualization environment, failed or corrupted VF migration can cause broader service disruption than a single local error path.

Paranoid total: **5**

## 3. Reachability analysis

The bug is not network reachable. It is reachable through GPU/VF operation and VF migration workflows, most likely from a local guest workload, reduced-privilege service, or virtualization management context that can cause BO movement while migration is active.

Namespaces do not directly make this broadly reachable, but container or guest access to a passed-through VF may reduce the practical privilege boundary compared with full host root. The path is not default for ordinary systems because it depends on Intel Xe SR-IOV VF CCS support and active VF migration.

Call-site confidence: **high**. The patch shows the relevant call path in `xe_bo_move()`, including attach before copy submission and detach after `dma_fence_wait()`.

## 4. Severity interpretation

This behaves more like **Actionable Moderate** than ordinary Moderate because it is a race in virtualization migration state and can affect GPU data integrity or VF availability. It should not be treated as a generic low-risk cleanup.

Theoretical impact includes limited confidentiality or integrity issues in migrated GPU data state. Realistic evidence supports device/VF state corruption and DoS, but the patch does not show UAF, OOB write, arbitrary write, host memory corruption, or a direct host privilege-escalation primitive.

## 5. One-sentence report phrase

A race in drm xe VF CCS attach and detach handling can leave VF migration observing partially copied or missing CCS metadata during in-flight BO moves, causing VF state corruption or denial of service with limited confidentiality and integrity concerns in the paranoid interpretation.

## 6. Manual review recommendation

**MANUAL CHECK REQUIRED**

This is not a proven host LPE, but it is a race in SR-IOV VF migration state involving GPU metadata save/restore, so environment-specific impact may be higher than the patch summary alone suggests.

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

Patch: drm/xe/vf: Fix VF CCS attach/detach race with in-flight BO moves [ Upstream
Commit: 35ba43b541117bfb595e4b807ba447cf4335cc7d
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=35ba43b541117bfb595e4b807ba447cf4335cc7d

Changed files:
  drivers/gpu/drm/xe/xe_bo.c
  drivers/gpu/drm/xe/xe_migrate.c
  drivers/gpu/drm/xe/xe_migrate.h
  drivers/gpu/drm/xe/xe_sriov_vf_ccs.c
  drivers/gpu/drm/xe/xe_sriov_vf_ccs.h

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=35ba43b541117bfb595e4b807ba447cf4335cc7d

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

The original Linux kernel CVE announcement for CVE-2026-68384 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68384

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:L/A:L
  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: 3
  Paranoid ActionableScore: 5

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 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).