[CVE-2026-53290][MODERATE 7.0] drm/xe/eustall: Fix drm_dev_put called before stream disable in close [ Upstream

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

CVE: CVE-2026-53290
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: YES
Patch: drm/xe/eustall: Fix drm_dev_put called before stream disable in close [ Upstream
Commit: bebce43f34b5feb8a760aa832eba81e0f8a38871
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=bebce43f34b5feb8a760aa832eba81e0f8a38871
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53290
Analysis date: Fri, 26 Jun 2026 17:05:52 -0400
ActionableScore: 6
ActionableScore lower bound: 5
Actionable bucket: Strong Important candidate / Actionable Moderate at minimum
Manual review required: YES

Summary:
A local use-after-free in the drm/xe EU stall stream close path can occur when `drm_dev_put()` releases the final DRM device reference before stream cleanup finishes, causing at least a kernel crash and requiring manual review for possible broader memory-corruption impact.

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ABOUT THIS REPORT
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The original Linux kernel CVE announcement for CVE-2026-53290 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53290

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-2026-53290	MODERATE	CHECK	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-672;*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 'A use-after-free can occur in the drm xe EU stall stream close path because drm_dev_put is called before the stream is disabled and its resources are freed. If this drops the last DRM device reference, device structures may be released while later cleanup still accesses gt and EU stall stream state. For the CVSS the PR:L is used because triggering requires a local process with access to the relevant DRM Xe stream interface, but not necessarily full administrator privileges in practical risk terms. The issue is not network reachable and is triggered through a local device file or driver control path. Impact is at least local denial of service via kernel crash. In the paranoid interpretation it may allow broader confidentiality or integrity impact because the bug class is use-after-free on kernel device structures and should be reviewed manually.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Strong Important candidate / Actionable Moderate at minimum (with actual score 6)  SKIP CVE-2026-53290  SKIP The Fixes patch not applied yet, so unlikely that actual: 9a0b11d4cf3b4324378c322b7043962e648681ed YES  NO NO unknown 	MAYBE	UAF HARDWARE KPANIC 	-	-	checked

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ACTIONABLESCORE ANALYSIS
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ActionableScore=6
ActionableScoreLower=5

## 1. ActionableScore

* Conservative score: 5
* Paranoid score: 6
* Final recommended bucket: **Strong Important candidate / Actionable Moderate at minimum**::

## 2. Signal breakdown

Conservative signals:

* Local unprivileged or reduced-privilege trigger: +1
  Triggering requires a local process that can open and close the relevant drm/xe EU stall stream interface. This is not remote, but may be reachable by non-root users depending on DRM device permissions.

* Generic memory corruption, strong corruption primitive: +2
  The commit explicitly describes a use-after-free caused by dropping the DRM device reference before later cleanup code accesses device-related structures.

* Real lifetime corruption: +1
  This is a reference lifetime ordering bug. `drm_dev_put()` may release the last reference before `xe_eu_stall_disable_locked()`, buffer destruction, and stream cleanup complete.

* Reliable kernel crash / strong DoS: +1
  If the last reference is dropped, subsequent dereferences of `gt`, `gt->eu_stall`, or stream state can crash the kernel.

* Hard lifecycle condition: -1
  Exploitation depends on the close path dropping the last DRM device reference at the vulnerable point, so this is more constrained than a generally reclaimable UAF.

* Rare or specialized interface: -1
  EU stall sampling is a specialized drm/xe feature, not a broad default kernel interface.

Paranoid additional signal:

* Weak LPE concern: +1
  The bug class is UAF in kernel device structures. A practical privilege-escalation primitive is not demonstrated, but memory lifetime corruption in a DRM driver is enough to require manual review.

## 3. Reachability analysis

The bug is local, not network reachable. A local process must have access to the drm/xe EU stall stream interface and then close it in a state where `drm_dev_put()` can drop the final device reference. Typical DRM access may be available to users in graphics-related groups or to container workloads when GPU devices are passed through, so PR:L is more appropriate than PR:H for practical triage. If the specific EU stall interface is gated by debugfs, perf permissions, or administrator-only controls in a deployment, the practical score may be lower.

The path is not a common packet-processing or filesystem path. It is device-driver specific and depends on Intel Xe hardware and the EU stall sampling feature.

## 4. Severity interpretation

This is not an ordinary Moderate cleanup issue because the patch explicitly fixes a use-after-free caused by incorrect reference-release ordering. Realistic impact is most clearly local denial of service through kernel crash. Theoretical privilege escalation cannot be ruled out solely from the patch because the stale access occurs after a final reference drop in kernel DRM device state, but no concrete reclaim, overwrite, or controlled object-confusion primitive is shown.

Overall this should be treated as Actionable Moderate at minimum, with Strong Important candidate handling for manual review.

## 5. One-sentence report phrase

A local use-after-free in the drm/xe EU stall stream close path can occur when `drm_dev_put()` releases the final DRM device reference before stream cleanup finishes, causing at least a kernel crash and requiring manual review for possible broader memory-corruption impact.

## 6. Manual review recommendation

MANUAL CHECK REQUIRED

Reason: the patch explicitly identifies a use-after-free in a kernel DRM driver reference-lifetime path. Even though realistic exploitation appears constrained and local, UAF-class bugs should not be auto-closed without manual analysis.

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

Patch: drm/xe/eustall: Fix drm_dev_put called before stream disable in close [ Upstream
Commit: bebce43f34b5feb8a760aa832eba81e0f8a38871
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=bebce43f34b5feb8a760aa832eba81e0f8a38871

Changed files:
  drivers/gpu/drm/xe/xe_eu_stall.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=bebce43f34b5feb8a760aa832eba81e0f8a38871

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

The original Linux kernel CVE announcement for CVE-2026-53290 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53290

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: 5
  Paranoid ActionableScore: 6

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).