[CVE-2026-53293][MODERATE REGULAR] drm/amdgpu: fix AMDGPU_INFO_READ_MMR_REG [ Upstream

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

CVE: CVE-2026-53293
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: drm/amdgpu: fix AMDGPU_INFO_READ_MMR_REG [ Upstream
Commit: 8c4254c8f5836e77ae83e7fc037f02b69f7a0977
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=8c4254c8f5836e77ae83e7fc037f02b69f7a0977
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53293
Analysis date: Fri, 26 Jun 2026 15:59:09 -0400
ActionableScore: 4
ActionableScore lower bound: 3
Actionable bucket: Borderline, manual review recommended / ordinary Moderate to Actionable Moderate depending on deployment
Manual review required: YES

Summary:
`AMDGPU_INFO_READ_MMR_REG could hold the GPU reset semaphore across memory allocation and copy_to_user, allowing a local DRM device user to trigger a deadlock or blocked reset path that results in denial of service.`

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

The original Linux kernel CVE announcement for CVE-2026-53293 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53293

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: YES

A detailed explanation of the methodology and priority rules is included
at the end of this message.

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

CVE-2026-53293	MODERATE	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-667;*CWE-833;CWE-703;Other CVSS 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '5.5';DESCR 'AMDGPU_INFO_READ_MMR_REG in the amdgpu info ioctl could hold the GPU reset semaphore while doing operations that may sleep or fault, including copy_to_user and memory allocation in the older flow. This creates a lock ordering and deadlock risk around GPU reset handling and user memory access. A local process with access to the AMDGPU DRM device can trigger the ioctl and may cause denial of service through a hang or blocked reset path. For the CVSS the PR:L is used for the paranoid score because reliable triggering requires local code execution with access to the DRM device, but this access is commonly available to non-root desktop or render group users. The issue is not network reachable. Impact is availability loss only based on the patch context, with no concrete UAF, OOB write, information leak, or privilege escalation primitive.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline, manual review recommended / ordinary Moderate to Actionable Moderate depending on deployment (with actual score 4)  SKIP CVE-2026-53293  SKIP No affected files built, so skip this CVE NO  - - unknown 	MAYBE	DEADLOCK NOMEMCHK HARDWARE 	-	-	checked

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

ActionableScore=4
ActionableScoreLower=3

## 1. ActionableScore

* Conservative score: 3
* Paranoid score: 4
* Final recommended bucket: **Borderline, manual review recommended / ordinary Moderate to Actionable Moderate depending on deployment**::

## 2. Signal breakdown

* `+1 Local unprivileged trigger`
  The path is a DRM ioctl reachable by a local process with access to the AMDGPU DRM device. On many desktop systems this may be available to non-root users via render or video group access.

* `+1 Reliable kernel crash / strong DoS`
  The bug is a lock ordering and sleeping-under-lock issue involving the reset semaphore, `copy_to_user()`, and memory allocation. The realistic impact is a deadlock, hang, or blocked GPU reset path.

* `+1 Broad/default/common subsystem`
  AMDGPU is a common DRM driver on systems with AMD GPUs, and the ioctl path is part of the normal userspace driver interface when the device is present.

* `+1 Availability impact realistic`
  Counted only in the paranoid score. A blocked reset path or deadlocked DRM ioctl can cause persistent local availability impact for GPU users and may require device reset, driver reload, or reboot.

* `-1 Hard or timing-dependent condition`
  Applied only to the conservative score. Reliable triggering likely depends on reset timing, faulting user memory, or interaction with GPU reset state.

Not counted:

* No remote reachability.
* No generic memory corruption.
* No UAF, double-free, OOB write, object confusion, or page-cache corruption.
* No plausible privilege escalation primitive from the patch context.
* No confidentiality or integrity impact is supported.

## 3. Reachability analysis

A local process can trigger the affected path by issuing `AMDGPU_INFO_READ_MMR_REG` through the AMDGPU DRM ioctl interface. This does not normally require full root privileges if the user has access to `/dev/dri` nodes, which is common for desktop users, render group members, or workloads with GPU device passthrough. Containers may lower the practical privilege requirement if DRM devices are delegated into the container.

The issue is not network reachable. It requires an AMDGPU device, the amdgpu driver, and access to the DRM device node. The path is not universal across all Linux systems, but it is common enough on AMD GPU systems that it should not be treated as a rare configuration-only bug.

## 4. Severity interpretation

This behaves like a local availability issue, not an Important-class memory corruption issue. The patch fixes incorrect lock ordering and sleeping operations while holding the reset semaphore. The realistic exploitation evidence supports local DoS through deadlock or blocked reset handling.

The theoretical impact should not be upgraded to privilege escalation because the patch does not show a reclaimable lifetime bug, attacker-controlled overwrite, UAF, OOB write, or sensitive-object access primitive. This is best treated as ordinary Moderate in strict CVSS terms, but borderline actionable because non-root DRM access is common and the resulting hang can affect system usability.

## 5. One-sentence report phrase

`AMDGPU_INFO_READ_MMR_REG could hold the GPU reset semaphore across memory allocation and copy_to_user, allowing a local DRM device user to trigger a deadlock or blocked reset path that results in denial of service.`

## 6. Manual review recommendation

MANUAL CHECK RECOMMENDED

Manual review is recommended because the practical severity depends on local DRM device permissions, whether unprivileged users can access the render node, and how severe a blocked AMDGPU reset is on the target deployment. It does not require Important handling unless additional evidence shows memory corruption or privilege escalation.

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

Patch: drm/amdgpu: fix AMDGPU_INFO_READ_MMR_REG [ Upstream
Commit: 8c4254c8f5836e77ae83e7fc037f02b69f7a0977
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=8c4254c8f5836e77ae83e7fc037f02b69f7a0977

Changed files:
  drivers/gpu/drm/amd/amdgpu/amdgpu_kms.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=8c4254c8f5836e77ae83e7fc037f02b69f7a0977

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

The original Linux kernel CVE announcement for CVE-2026-53293 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53293

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: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: 3
  Paranoid ActionableScore: 4

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).