[CVE-2026-68383][MODERATE 7.0] drm/xe/guc: Keep scheduler timeline name alive [ Upstream

[CVE-2026-68383][MODERATE 7.0] drm/xe/guc: Keep scheduler timeline name alive [ Upstream

[AL-KERNEL]

CVE: CVE-2026-68383
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: drm/xe/guc: Keep scheduler timeline name alive [ Upstream
Commit: 77fd62412431e8c80ef2ad61466bc76fe425f80a
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=77fd62412431e8c80ef2ad61466bc76fe425f80a
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68383
Analysis date: Mon, 10 Aug 2026 19:01:03 -0400
ActionableScore: 5
ActionableScore lower bound: 4
Actionable bucket: Actionable Moderate at minimum
Manual review required: NO

Summary:
A stale scheduler timeline name pointer in drm xe GuC can outlive the freed exec queue name storage, allowing local DRM users to trigger a UAF-style stale read with possible limited information disclosure or kernel crash.

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

The original Linux kernel CVE announcement for CVE-2026-68383 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68383

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: NO

A detailed explanation of the methodology and priority rules is included
at the end of this message.

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

CVE-2026-68383	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:N/A:H';*CWE-416;CWE-825;*CWE-664;BEST CVSS score: '5.3';DESCR 'drm xe GuC scheduler fences can keep a pointer to the timeline name after the original xe_exec_queue and q name storage are freed. Later fence or scheduler code may read that stale name pointer, which is a use after free style lifetime bug and can cause an invalid kernel read, a crash, or limited information exposure if reused memory is formatted as a string. For the CVSS the PR:L is used because a local user with access to the DRM render node can plausibly create and destroy xe exec queues without full administrator privileges. The issue is not network reachable and requires local interaction with the GPU driver control path. Impact is at least local denial of service and possible limited confidentiality impact from stale string reads, while privilege escalation is not strongly supported by this patch context.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Actionable Moderate at minimum (with actual score 5)  SKIP CVE-2026-68383 UNKNOWN SKIP The Fixes patch not applied yet, so unlikely that actual: 6bd90e700b4285e6a7541e00f969cab0d696adde YES  NO NO unknown 	MAYBE	LOCK UAF HARDWARE MEMORY  DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH INCREASED_TO_MODERATE70_BASED_ON_ACTIONABLESCOREHIGHEREQTHAN5 DECREASED_TO_MODERATEREG_BASED_ON_FALSEPOSCHECKOFKP	-	-	checked

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

ActionableScore=5
ActionableScoreLower=4

## 1. ActionableScore

* Conservative score: 4
* Paranoid score: 5
* Final recommended bucket: **Actionable Moderate at minimum**::

## 2. Signal breakdown

* Local unprivileged trigger: +1
  A local user with access to the DRM render node can plausibly create and destroy xe exec queues without full administrator privileges.

* Memory corruption, weak/indirect corruption candidate: +1
  The scheduler keeps a pointer to `q->name` after the exec queue can be freed. This is a stale pointer / UAF-style read, but the patch does not show overwrite, callback control, type confusion, or attacker-controlled reclaim.

* Real lifetime corruption: +1
  The fix explicitly changes object lifetime by storing the name inside `struct xe_guc_exec_queue`, which follows the scheduler RCU-deferred lifetime.

* Confidentiality impact plausible: +1
  If the stale name pointer is later formatted or exposed through fence / scheduler reporting paths, reused freed memory could be read as a string. This is limited and not a demonstrated info leak primitive.

* Reliable kernel crash / strong DoS: +1 in paranoid score only
  A stale kernel string pointer can plausibly cause invalid reads, KASAN reports, or crashes, but the provided patch does not demonstrate a reliable host-wide crash path.

No points awarded for privilege escalation. No evidence of attacker-controlled reclaim, write-after-free, callback dispatch, type confusion, or arbitrary write is present.

## 3. Reachability analysis

The bug is locally reachable through the Intel xe DRM GPU driver path. In typical desktop or workstation deployments, DRM render nodes may be accessible to non-root users, so PR:L is the practical assumption. Containers may expose DRM render nodes intentionally for GPU acceleration, which can preserve local unprivileged reachability inside delegated environments.

The issue is not network reachable. It depends on xe GuC scheduling and scheduler fence lifetime behavior, so it is hardware and driver dependent, but not an exotic debug-only path. Call-site confidence: high, because the patch shows the affected initialization call passing `q->name` into `xe_sched_init()` and then changes it to use `ge->name`.

## 4. Severity interpretation

This behaves like an actionable Moderate lifetime bug rather than a clear Important-class vulnerability. The theoretical concern is a UAF-style stale pointer read from scheduler fence code after the exec queue name storage is freed. Realistic impact is limited information exposure or local DoS. Privilege escalation is not strongly supported because the stale object is a name string and the patch does not show attacker-controlled replacement, writable stale access, function pointer use, refcount takeover, or object confusion.

The paranoid score reaches 5 because kernel lifetime bugs in GPU scheduler/fence paths deserve manual review even when the visible primitive is read-only and constrained.

## 5. One-sentence report phrase

A stale scheduler timeline name pointer in drm xe GuC can outlive the freed exec queue name storage, allowing local DRM users to trigger a UAF-style stale read with possible limited information disclosure or kernel crash.

## 6. Manual review recommendation

MANUAL CHECK RECOMMENDED

This should not be auto-closed because it is a real lifetime/UAF-style bug in a GPU scheduler fence path, but the available patch evidence supports only constrained stale string reads rather than a strong privilege-escalation primitive.

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

Patch: drm/xe/guc: Keep scheduler timeline name alive [ Upstream
Commit: 77fd62412431e8c80ef2ad61466bc76fe425f80a
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=77fd62412431e8c80ef2ad61466bc76fe425f80a

Changed files:
  drivers/gpu/drm/xe/xe_guc_exec_queue_types.h
  drivers/gpu/drm/xe/xe_guc_submit.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=77fd62412431e8c80ef2ad61466bc76fe425f80a

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

The original Linux kernel CVE announcement for CVE-2026-68383 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68383

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: Not available
  The Best / paranoid CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:H
  The Best / paranoid CVSS score: 5.3

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: 4
  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).