[CVE-2026-72361][MODERATE 7.0] drm/xe/hw_engine: Fix double-free of managed BO in error path [ Upstream commit 7ac3cae7a251d28e9079de07a991bd4eb2bb7fd8 ]

[CVE-2026-72361][MODERATE 7.0] drm/xe/hw_engine: Fix double-free of managed BO in error path [ Upstream commit 7ac3cae7a251d28e9079de07a991bd4eb2bb7fd8 ]

[AL-KERNEL]

CVE: CVE-2026-72361
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: YES
Patch: drm/xe/hw_engine: Fix double-free of managed BO in error path [ Upstream commit 7ac3cae7a251d28e9079de07a991bd4eb2bb7fd8 ]
Commit: 1f6b44d555ecce61e249220f2ca4d75cdb90caf6
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=1f6b44d555ecce61e249220f2ca4d75cdb90caf6
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72361
Analysis date: Sat, 15 Aug 2026 20:43:35 -0400
ActionableScore: 5
ActionableScore lower bound: 4
Actionable bucket: Actionable Moderate at minimum
Manual review required: YES

Summary:
No one-sentence report phrase was found.

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

The original Linux kernel CVE announcement for CVE-2026-72361 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72361

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.

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

CVE-2026-72361	MODERATE	CHECK WITH IMPACT FROM ORIG NN MODERATE	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H';CWE-415;*CWE-672;CWE-703;CWE-415;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '6.4';DESCR 'A double free can occur in the drm xe hardware engine initialization error path because a BO allocated through xe_managed_bo_create_pin_map already has devm managed cleanup, but the old error path also freed it explicitly with xe_bo_unpin_map_no_vm. If probe later fails and devm unwinds, the same managed BO can be released again, creating a kernel memory corruption condition. For the CVSS the PR:H is used because reliable triggering typically requires administrative control over driver probing, device binding, fault injection, or a failing GPU initialization path. The issue is not network reachable and is tied to a local driver probe failure path rather than packet traffic or a remote protocol. Impact is at least local denial of service via kernel crash. For the paranoid score, the highest still defensible interpretation is C:H I:H A:H because the bug class is double free in kernel memory management, but exploitation beyond crash is not demonstrated by the patch context.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Actionable Moderate at minimum (with actual score 5)  SKIP CVE-2026-72361 UNKNOWN SKIP The Fixes patch not applied yet, so unlikely that actual: 0e1a47fcabc8ffa6f460c60c2caa04e51170fa22 YES  NO NO unknown 	MAYBE	DANGER INIT ERRORPATH UAF HARDWARE KPANIC 	-	-	checked

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ACTIONABLESCORE ANALYSIS
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ActionableScore=5
ActionableScoreLower=4

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

2. Signal breakdown
* Memory corruption, Strong corruption primitive: +2. The patch fixes an explicit double-free of a managed BO in the drm/xe driver error path.
* Real lifetime corruption: +1. The same BO is freed manually and then later released again by devm unwind.
* Reliable kernel crash / strong DoS: +1. A double-free during probe failure can plausibly crash the kernel or leave the driver/device state unusable.
* Privileged kernel/device-management memory corruption path: +1. The issue is in GPU driver initialization and devm cleanup logic.
* Requires admin/root/CAP_* in typical deployments: -2. Reliable triggering normally requires control over driver probing, device binding, module load/unload, fault injection, or equivalent privileged device-management operations.
* Hard or unreliable trigger / special condition: -1. The vulnerable path requires a specific probe failure after xe_managed_bo_create_pin_map() and before normal hw_engine_init() completion.
* Paranoid uplift: +1. Double-free is a kernel memory lifetime corruption class, so manual review is justified even though attacker-controlled reclaim or a demonstrated LPE primitive is not shown.

3. Reachability analysis
The bug is locally reachable through a driver probe or initialization failure path, not through a network protocol. In normal deployments, an attacker would need administrative control over GPU driver binding, module lifecycle, device reset/probe behavior, or a fault-injection style setup. A compromised or abnormal device/firmware state could influence the failure path, but this is better treated as device-mediated or firmware-mediated influence rather than remote reachability. Namespace/container delegation does not normally make this reachable to an unprivileged user unless the environment exposes GPU device management or driver binding controls to a reduced-privilege actor. Call-site confidence: high, because the changed error path and cleanup consequence are visible in the patch and commit message.

4. Severity interpretation
This is not an ordinary low-risk cleanup because the fixed condition is a real double-free in kernel memory management. Realistic exploitation evidence points mainly to local privileged DoS during GPU probe failure, and the patch does not show attacker-controlled reclaim, arbitrary write, callback control, or a concrete privilege-escalation primitive. The conservative score is therefore borderline/manual-review level. The paranoid score reaches Actionable Moderate because double-free lifetime bugs in privileged driver initialization can be under-triaged if treated as mere error-path cleanup. It is not a Strong Important candidate without evidence of unprivileged reachability or a stronger exploitation primitive.

5. One-sentence report phrase
A double-free in the drm/xe hardware engine initialization error path can occur when a devm-managed BO is explicitly freed and then released again during probe unwind, creating a local privileged kernel memory corruption and DoS condition that warrants manual review.

6. Manual review recommendation
MANUAL CHECK REQUIRED. This is a kernel double-free and lifetime-management bug, even though practical triggering appears limited to privileged or device-mediated probe failure scenarios.

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

Patch: drm/xe/hw_engine: Fix double-free of managed BO in error path [ Upstream commit 7ac3cae7a251d28e9079de07a991bd4eb2bb7fd8 ]
Commit: 1f6b44d555ecce61e249220f2ca4d75cdb90caf6
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=1f6b44d555ecce61e249220f2ca4d75cdb90caf6

Commit description:

The error path in hw_engine_init() explicitly frees a BO allocated
with xe_managed_bo_create_pin_map() via xe_bo_unpin_map_no_vm().
Since the managed BO already has a devm cleanup action registered,
this causes a double-free when devm unwinds during probe failure.

Remove the explicit free and let devm handle it, consistent with
all other xe_managed_bo_create_pin_map() callers.

Fixes: 0e1a47fcabc8 ("drm/xe: Add a helper for DRM device-lifetime BO create")
Assisted-by: Claude:claude-opus-4.6
Reviewed-by: Zongyao Bai <zongyao.bai@intel.com>
Link: https://patch.msgid.link/20260626210631.3887291-1-shuicheng.lin@intel.com
Signed-off-by: Shuicheng Lin <shuicheng.lin@intel.com>
(cherry picked from commit e459a3bdeb117be496d7f229e2ea1f6c9fe4080b)
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat -rw-r--r-- drivers/gpu/drm/xe/xe_hw_engine.c 4

Changed files:
  drivers/gpu/drm/xe/xe_hw_engine.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=1f6b44d555ecce61e249220f2ca4d75cdb90caf6

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

The original Linux kernel CVE announcement for CVE-2026-72361 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72361

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:H/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS vector: AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
  The Best / paranoid CVSS score: 6.4

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: 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).