[CVE-2026-53375][MODERATE 7.0] drm/amdgpu/vce: Prevent partial address patches

[CVE-2026-53375][MODERATE 7.0] drm/amdgpu/vce: Prevent partial address patches

[AL-KERNEL]

CVE: CVE-2026-53375
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: drm/amdgpu/vce: Prevent partial address patches
Commit: 2d66d1f5d8c0434e9a5ad21cc6eaf3a5e32141d5
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=2d66d1f5d8c0434e9a5ad21cc6eaf3a5e32141d5
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53375
Analysis date: Sun, 19 Jul 2026 06:43:44 -0400
ActionableScore: 5
ActionableScore lower bound: 3
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-2026-53375 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53375

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-2026-53375	MODERATE	CHECK WITH IMPACT FROM ORIG NN LOW	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H';*CWE-20;*CWE-787;CWE-823;Other CVSS 'AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:H';BEST CVSS score: '7.8';DESCR 'amdgpu VCE command submission did not reject relocation records where only one 32 bit half of a patched address is inside the IB bounds. A local user with access to the AMDGPU DRM render or card device may craft a command stream that causes partial address patching and a bad address to be passed to firmware. For the CVSS the PR:L is used because reliable triggering requires local code execution with access to the GPU submission interface, but not full administrative privileges in common desktop or compute deployments. The issue is not network reachable. Impact is at least GPU reset or kernel denial of service, and the out of bounds or bad address patching pattern is a plausible memory corruption candidate that should be reviewed manually.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Actionable Moderate at minimum (with actual score 4)  SKIP CVE-2026-53375 UNKNOWN SKIP No affected files built, so skip this CVE NO  - - unknown 	MAYBE	OOB SIMPLEFIX HARDWARE  INCREASED_TO_HIGH_BASED_ON_GUESSCVSS DECREASED_TO_MODERATE70_BASED_ON_ACTIONABLESCORELOWERTHAN7 DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN5	-	-	checked

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ACTIONABLESCORE ANALYSIS
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1. ActionableScore

ActionableScore=5
ActionableScoreLower=3

* Conservative score: 3
* Paranoid score: 5
* Final recommended bucket: **Actionable Moderate at minimum**

2. Signal breakdown

* Local unprivileged trigger: +1. A local process with access to the AMDGPU DRM submission interface or render node may be able to submit the affected VCE command stream.
* Constrained kernel or GPU buffer overwrite candidate: +1. The patch adds bounds checks for `lo` and `hi` before address patching, so the bug is more than pure bookkeeping, but the write appears constrained to VCE relocation patching and the payload is address-derived rather than an arbitrary attacker-chosen byte stream.
* Reliable kernel crash or strong DoS: +1. A bad address passed to firmware can plausibly cause GPU hang, reset, or driver level denial of service.
* Privileged kernel or device-management corruption path: +1 in paranoid scoring. The affected path is GPU firmware command submission and address patching, which is a trusted device interaction path.
* Weak LPE concern: +1 in paranoid scoring only. Partial address patching into a firmware-consumed command stream is a plausible corruption sink, but no concrete host kernel arbitrary write, reclaim primitive, or privilege escalation chain is shown.
* Constrained primitive or no attacker-controlled payload: -1. The patch does not show a fully attacker-controlled target and payload primitive.

3. Reachability analysis

The likely trigger is local command submission through AMDGPU VCE paths. This does not appear network reachable. In typical desktop or GPU compute deployments, DRM render node access may be available to non-root users in the video or render group, so PR:L is the practical interpretation rather than PR:H. Containers may inherit exposure if GPU devices are passed through. The path is hardware and feature dependent because it requires AMDGPU VCE support, so exposure is narrower than core kernel networking or filesystem code, but it is still reachable through ordinary GPU userspace interfaces when the device is available.

Call-site confidence: medium. The provided patch shows the validation point and affected helper, but not the full caller chain or the final writes into the IB.

4. Severity interpretation

This is not an ordinary Low issue because it involves address patching in a GPU firmware command stream and missing bounds validation for relocation indices. The conservative interpretation is a local DoS or GPU reset class issue with constrained corruption characteristics. The paranoid interpretation treats the partial address patch as a weak device memory corruption candidate that deserves manual review, but the patch does not justify assuming arbitrary host kernel code execution or a strong LPE primitive.

5. One-sentence report phrase

A local user with access to the AMDGPU VCE command submission path may craft relocation indices where only one address half is valid, causing partial address patching and a bad firmware-consumed address that can lead to GPU or kernel denial of service and warrants manual review for constrained corruption impact.

6. Manual review recommendation

MANUAL CHECK REQUIRED

Manual review is required because the bug is in a GPU firmware address patching path and may represent more than a simple validation error, even though the demonstrated impact is closer to constrained corruption or DoS than proven privilege escalation.

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

Patch: drm/amdgpu/vce: Prevent partial address patches
Commit: 2d66d1f5d8c0434e9a5ad21cc6eaf3a5e32141d5
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=2d66d1f5d8c0434e9a5ad21cc6eaf3a5e32141d5

Commit description:

In the case that only one of lo/hi is valid, the patching could result
in a bad address written to in FW.

Signed-off-by: Benjamin Cheng <benjamin.cheng@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Changed files:
  drivers/gpu/drm/amd/amdgpu/amdgpu_vce.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=2d66d1f5d8c0434e9a5ad21cc6eaf3a5e32141d5

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

The original Linux kernel CVE announcement for CVE-2026-53375 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53375

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:L/PR:L/UI:N/S:U/C:N/I:L/A:H
  The Best / paranoid CVSS vector: AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
  The Best / paranoid CVSS score: 7.8

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: 3
  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).