[CVE-2026-72244][MODERATE REGULAR] gpu/buddy: bail out of try_harder when alignment cannot be honoured [ Upstream

[CVE-2026-72244][MODERATE REGULAR] gpu/buddy: bail out of try_harder when alignment cannot be honoured [ Upstream

[AL-KERNEL]

CVE: CVE-2026-72244
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: gpu/buddy: bail out of try_harder when alignment cannot be honoured [ Upstream
Commit: 4289531106ee175a6eb45db7d4f2734d1dae9887
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=4289531106ee175a6eb45db7d4f2734d1dae9887
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72244
Analysis date: Sat, 15 Aug 2026 03:49:04 -0400
ActionableScore: 3
ActionableScore lower bound: 2
Actionable bucket: Ordinary Moderate / Borderline actionable only under GPU availability impact assumptions
Manual review required: NO

Summary:
A local user with access to GPU DRM allocation paths may trigger a gpu buddy allocator alignment bug that can return a misaligned contiguous range, potentially causing GPU faults, reset, or denial of service, but the patch does not show a concrete memory corruption or privilege escalation primitive.

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

The original Linux kernel CVE announcement for CVE-2026-72244 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72244

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 REGULAR
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-2026-72244	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:N/I:N/A:H';CWE-682;CWE-754;**CWE-400;Other CVSS 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '4.7';DESCR 'The GPU buddy contiguous allocation fallback can return a range whose start offset does not satisfy the caller requested min_block_size alignment. This breaks the allocator contract and may cause GPU driver or hardware paths to operate on incorrectly aligned GPU memory. For the CVSS the PR:L is used because a local user process with access to GPU DRM interfaces or render nodes may be able to request allocations that reach this path, while root privileges are not inherently required in common desktop or compute deployments. The issue is not network reachable and requires local interaction with the GPU memory allocation path. Impact is primarily denial of service through allocation failure, GPU fault, GPU reset, or degraded graphics and compute availability. No concrete UAF, OOB write, arbitrary write, or information leak primitive is shown by the patch context, so confidentiality and integrity are not raised in the selected scores.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Borderline actionable only under GPU availability impact assumptions (with actual score 3)  SKIP CVE-2026-72244 UNKNOWN SKIP No affected files built, so skip this CVE NO  - - unknown 	MAYBE	INIT LOG HARDWARE  INCREASED_FROM_LOW_TO_MODERATE70_BASED_ON_ACTIONABLESCOREHIGHEREQTHAN3 DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN5	-	-	checked

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

ActionableScore=3
ActionableScoreLower=2

## 1. ActionableScore

* Conservative score: 2
* Paranoid score: 3
* Final recommended bucket: **Ordinary Moderate / Borderline actionable only under GPU availability impact assumptions**

## 2. Signal breakdown

Conservative signals:

* Local unprivileged trigger: +1. A local process with access to GPU DRM render nodes may be able to request GPU memory allocations that reach the buddy allocator path.
* Availability impact realistic: +1. A misaligned returned allocation can plausibly cause allocation failure, GPU fault, GPU reset, or degraded graphics and compute availability.
* Broad/default/common subsystem: +1. DRM GPU memory allocation is common on desktop, workstation, and GPU compute systems.
* Hard or unreliable condition: -1. Triggering depends on allocator fragmentation, contiguous fallback behavior, size, and min_block_size alignment conditions.

Paranoid additional signal:

* Memory layout invariant restoration: +1. The patch restores the invariant that returned contiguous allocation offsets must satisfy the caller requested min_block_size alignment.

Not awarded:

* No generic memory corruption signal. The patch does not show UAF, double free, OOB write, arbitrary write, refcount misuse, or type confusion.
* No privilege escalation signal. There is no supported path to credential overwrite, controlled kernel object reuse, callback control, or cross process memory exposure.
* No high-control GPU API bonus. The patch shows object allocation alignment correction, not attacker control over kernel object lifetime, callback targets, DMA mappings, or page ownership.
* No network reachability.

## 3. Reachability analysis

The likely trigger is local access to GPU allocation paths, typically through DRM render nodes or GPU compute graphics APIs. Root is not inherently required on common desktop or compute deployments where render nodes are accessible to users. Containers may matter if GPU devices are passed through, but the bug does not itself imply a container escape. The path is not network reachable. Realistic exploitation requires a suitable GPU driver using this buddy allocator path plus allocator state that enters the try_harder contiguous fallback and returns a candidate with unsuitable alignment.

## 4. Severity interpretation

This behaves more like an ordinary Moderate or Low like availability issue than an Important kernel vulnerability. The theoretical concern is that an allocator contract violation can propagate into GPU driver or hardware behavior, but the patch does not support a concrete memory corruption or privilege escalation primitive. The realistic impact is local GPU availability degradation or reset rather than host compromise.

## 5. One-sentence report phrase

A local user with access to GPU DRM allocation paths may trigger a gpu buddy allocator alignment bug that can return a misaligned contiguous range, potentially causing GPU faults, reset, or denial of service, but the patch does not show a concrete memory corruption or privilege escalation primitive.

## 6. Manual review recommendation

NO MANUAL CHECK NEEDED

This can be handled as non-urgent unless the affected product exposes GPU devices to untrusted tenants or a specific driver caller is later shown to turn the misaligned allocation into cross-object memory corruption or data exposure.

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

Patch: gpu/buddy: bail out of try_harder when alignment cannot be honoured [ Upstream
Commit: 4289531106ee175a6eb45db7d4f2734d1dae9887
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=4289531106ee175a6eb45db7d4f2734d1dae9887

Changed files:
  drivers/gpu/buddy.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=4289531106ee175a6eb45db7d4f2734d1dae9887

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

The original Linux kernel CVE announcement for CVE-2026-72244 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72244

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:H/PR:L/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS score: 4.7

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: 2
  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: MODERATE
KPANIC detected for this report: NO
Published priority for this report (same as in Subject): MODERATE REGULAR

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).