[CVE-2026-46201][LOW] drm/xe: Fix dma-buf attachment leak in xe_gem_prime_import()

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

CVE: CVE-2026-46201
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: drm/xe: Fix dma-buf attachment leak in xe_gem_prime_import()
Commit: d394669e194936d7ce15284a24a5ae334c4c5b74
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=d394669e194936d7ce15284a24a5ae334c4c5b74
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-46201
Analysis date: Thu, 28 May 2026 07:03:35 -0400
ActionableScore: 3
ActionableScore lower bound: 1
Actionable bucket: Ordinary Moderate / Low-like
Manual review required: NO

Summary:
A missing dma_buf_detach() in the xe PRIME import error path can leak dma-buf attachments after failed imports, allowing local resource exhaustion only if the failure path can be repeatedly triggered.

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

The original Linux kernel CVE announcement for CVE-2026-46201 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-46201

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: LOW
Manual review required: NO

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-2026-46201	LOW	CHECK	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H';*CWE-772;*CWE-401;CWE-404;Other CVSS 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '5.5';DESCR 'A dma buf attachment leak in xe_gem_prime_import() can occur when dma_buf_dynamic_attach succeeds but xe_dma_buf_init_obj() later fails. The leaked attachment may keep kernel or GPU import resources referenced across repeated failed PRIME import attempts and can lead to local resource exhaustion. For the CVSS the PR:L is used because triggering requires a local user or process with access to the DRM xe device and dma buf import operations, not full administrator rights. The issue is not network reachable and does not provide an evident memory corruption, information disclosure, or privilege escalation primitive. Impact is denial of service only, with severity depending on how reliably the failure path can be repeated on the target system.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 2)	YES	INIT LEAK UAF DMAorINTERRUPT HARDWARE MEMORY  DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3	YES	NO	checked

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ACTIONABLESCORE ANALYSIS
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ActionableScore=3
ActionableScoreLower=1

## 1. ActionableScore

* Conservative score: 1
* Paranoid score: 3
* Final recommended bucket: **Ordinary Moderate / Low-like**::

## 2. Signal breakdown

Conservative signals:

* Local unprivileged trigger: +1
  PRIME dma-buf import can be reachable by a local user with access to the DRM xe device or render node.

Paranoid additional signals:

* Availability impact realistic: +1
  Repeated failed imports could leak dma-buf attachments and gradually exhaust kernel or GPU-related resources.

* Broad/default/common subsystem exposure: +1
  DRM render-node access is common on desktop and GPU compute systems, although this specific issue is limited to the Intel xe driver.

Discounts and non-applied signals:

* No memory corruption signal applied.
  The patch fixes a missing dma_buf_detach() on an error path, not UAF, OOB write, type confusion, or arbitrary write.

* No LPE signal applied.
  The commit does not show a reclaim primitive, controlled overwrite, or object confusion.

* No remote/network signal applied.
  This is a local DRM dma-buf import path.

## 3. Reachability analysis

A local user or process with access to the xe DRM device can potentially reach xe_gem_prime_import() through PRIME dma-buf import operations. In typical systems, render-node permissions may make this available to non-root graphical or compute users. Containers may lower practical barriers if GPU devices are passed through, but the bug remains local to a process with DRM device access. Exploitation also requires the error path where dma_buf_dynamic_attach() succeeds but xe_dma_buf_init_obj() fails, so reliable resource exhaustion depends on whether that failure can be repeatedly induced.

## 4. Severity interpretation

This behaves like an ordinary Moderate or Low-like resource leak, not an Important memory-corruption issue. The realistic impact is local denial of service through accumulated leaked attachments. Theoretical severity is limited because there is no supported confidentiality impact, integrity impact, UAF, double free, object confusion, or privilege escalation primitive.

## 5. One-sentence report phrase

A missing dma_buf_detach() in the xe PRIME import error path can leak dma-buf attachments after failed imports, allowing local resource exhaustion only if the failure path can be repeatedly triggered.

## 6. Manual review recommendation

NO MANUAL CHECK NEEDED

Reason: this is a local resource leak without memory corruption or privilege escalation evidence. Manual review is only worth considering for multi-tenant GPU systems where untrusted users have broad xe render-node access.

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

Patch: drm/xe: Fix dma-buf attachment leak in xe_gem_prime_import()
Commit: d394669e194936d7ce15284a24a5ae334c4c5b74
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=d394669e194936d7ce15284a24a5ae334c4c5b74

Commit description:

When xe_dma_buf_init_obj() fails, the attachment from
dma_buf_dynamic_attach() is not detached. Add dma_buf_detach() before
returning the error. Note: we cannot use goto out_err here because
xe_dma_buf_init_obj() already frees bo on failure, and out_err would
double-free it.

Fixes: dd08ebf ("drm/xe: Introduce a new DRM driver for Intel GPUs")
Cc: stable@vger.kernel.org
Assisted-by: Claude:claude-opus-4.6
Reviewed-by: Mattheq Brost <matthew.brost@intel.com>
Link: https://patch.msgid.link/20260408175255.3402838-5-shuicheng.lin@intel.com
Signed-off-by: Shuicheng Lin <shuicheng.lin@intel.com>
(cherry picked from commit a828eb1 )
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Changed files:
  drivers/gpu/drm/xe/xe_dma_buf.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=d394669e194936d7ce15284a24a5ae334c4c5b74

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

The original Linux kernel CVE announcement for CVE-2026-46201 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-46201

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:L
  The Best / paranoid CVSS vector: AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS score: 5.5

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: 1
  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: LOW
KPANIC detected for this report: NO
Published priority for this report (same as in Subject): LOW

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).