[CVE-2026-68108][MODERATE 7.0] drm/amdgpu/vce: fix integer overflow in image size

[CVE-2026-68108][MODERATE 7.0] drm/amdgpu/vce: fix integer overflow in image size

[AL-KERNEL]

CVE: CVE-2026-68108
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: YES
Patch: drm/amdgpu/vce: fix integer overflow in image size
Commit: a07430abd556de3707adfcadcc60db3fa64e4b2b
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=a07430abd556de3707adfcadcc60db3fa64e4b2b
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68108
Analysis date: Mon, 10 Aug 2026 09:34:22 -0400
ActionableScore: 8
ActionableScore lower bound: 6
Actionable bucket: Strong Important candidate / Actionable Moderate at minimum
Manual review required: YES

Summary:
A local user with access to AMDGPU VCE command submission can provide oversized image dimensions that overflow a 32-bit size calculation, bypass validation, and allow GPU firmware out-of-bound memory access with possible DoS and potential confidentiality or integrity impact.

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ABOUT THIS REPORT
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The original Linux kernel CVE announcement for CVE-2026-68108 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68108

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-2026-68108	MODERATE	CHECK WITH IMPACT FROM ORIG NN IMPORTANT	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-190;*CWE-787;CWE-119;Other CVSS 'AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:H';BEST CVSS score: '7.8';DESCR 'An integer overflow in the AMDGPU VCE command stream parser can occur when a local user submits malicious image dimensions such as 65536 by 65536. The 32 bit size calculation can wrap to 0 or another small value, bypassing buffer size validation and allowing the GPU firmware to perform out-of-bound memory access. For the CVSS the PR:L is used because reliable triggering requires local access to the DRM or render node interface, but it does not normally require full administrative privileges. The issue is not network reachable and requires local code execution on a system with affected AMDGPU VCE support. Impact is at least denial of service via GPU reset or kernel crash. Because the bug class is integer overflow leading to out-of-bound firmware memory access, the worst case may include confidentiality or integrity impact and should be reviewed manually.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Strong Important candidate / Actionable Moderate at minimum (with actual score 8)  SKIP CVE-2026-68108 UNKNOWN SKIP No affected files built, so skip this CVE NO  - - unknown 	MAYBE	WRITE OOB SIMPLEFIX HARDWARE  KPANIC INCREASED_TO_HIGH_BASED_ON_GUESSCVSS DECREASED_TO_MODERATE7_BASED_ON_FALSEPOSCHECKOFKP	-	-	checked

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ACTIONABLESCORE ANALYSIS
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ActionableScore=8
ActionableScoreLower=6

## 1. ActionableScore

* Conservative score: 6
* Paranoid score: 8
* Final recommended bucket: **Strong Important candidate / Actionable Moderate at minimum**::

## 2. Signal breakdown

Triggered signals:

* Local unprivileged trigger: +1
  A local user with access to the AMDGPU DRM render or video command submission path can submit a crafted VCE command stream.

* Memory corruption, strong corruption primitive: +2
  The bug is a 32-bit integer overflow that bypasses buffer-size validation and allows GPU firmware to perform out-of-bound memory access.

* Reliable kernel crash / strong DoS: +1
  Out-of-bound GPU firmware memory access can realistically cause GPU reset, driver failure, or kernel crash.

* Privileged kernel/device-management memory corruption path: +1
  The corrupted operation happens in a GPU firmware / driver command-processing path, which is a trusted device-management context.

* Confidentiality impact plausible: +1
  OOB firmware memory access may plausibly read unintended GPU/GTT/VRAM memory, though no concrete leak primitive is demonstrated.

* Integrity impact plausible: +1
  OOB firmware memory access may plausibly corrupt GPU/GTT/VRAM memory or adjacent command/buffer state.

* Broad/default/common subsystem exposure: +1
  AMDGPU DRM render interfaces are commonly exposed to local desktop or compute users on affected AMD systems.

Negative / limiting signals:

* Corruption primitive constrained or target not fully demonstrated: -1
  The patch shows OOB firmware memory access, but does not demonstrate attacker-controlled target selection, arbitrary write, or a working LPE chain.

Conservative score omits the weak LPE bonus and treats the primitive as serious but still constrained. Paranoid score adds the broader exposure and worst-case C/I concern because the patch explicitly describes security-relevant OOB firmware memory access.

## 3. Reachability analysis

The bug is locally reachable through malicious VCE command streams submitted to AMDGPU. In typical deployments, this does not require full root privileges if the user has access to `/dev/dri/renderD*` or equivalent GPU render/video interfaces. Containers can affect reachability if GPU devices are passed through or exposed to workloads, but without GPU device access the bug is not reachable.

The issue is not network-triggerable by itself. Exploitation requires an affected AMDGPU device with VCE support and a path allowing local command submission. This is hardware-dependent but not an obscure kernel debug path.

## 4. Severity interpretation

This is stronger than an ordinary Moderate because the patch explicitly fixes an integer overflow leading to out-of-bound memory access by GPU firmware. Realistic impact is at least local DoS through GPU reset or kernel crash. Practical privilege escalation is not demonstrated, but the bug class and firmware-mediated OOB memory access make confidentiality and integrity impact technically plausible enough for manual review.

This should be treated as an Actionable Moderate at minimum and a Strong Important candidate under the paranoid interpretation.

## 5. One-sentence report phrase

A local user with access to AMDGPU VCE command submission can provide oversized image dimensions that overflow a 32-bit size calculation, bypass validation, and allow GPU firmware out-of-bound memory access with possible DoS and potential confidentiality or integrity impact.

## 6. Manual review recommendation

MANUAL CHECK REQUIRED

The issue involves integer overflow followed by firmware-mediated out-of-bound memory access in a GPU command submission path. Even though a concrete LPE primitive is not shown, the combination of local user reachability, OOB memory access, and trusted device context makes auto-closing unsafe.

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

Patch: drm/amdgpu/vce: fix integer overflow in image size
Commit: a07430abd556de3707adfcadcc60db3fa64e4b2b
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=a07430abd556de3707adfcadcc60db3fa64e4b2b

Commit description:

Fix a security vulnerability where malicious VCE command streams
with oversized dimensions (e.g. 65536×65536) cause 32-bit integer
overflow, wrapping the calculated buffer size to 0. This bypasses
validation and allows GPU firmware to perform out-of-bound memory
access.

The fix uses 64-bit arithmetic to detect overflow and rejects
invalid dimensions before they reach the hardware.

V2: remove redundant check
V3: modify max height value
V4: remove size64

Signed-off-by: Boyuan Zhang <boyuan.zhang@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit cbe408d )
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=a07430abd556de3707adfcadcc60db3fa64e4b2b

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

The original Linux kernel CVE announcement for CVE-2026-68108 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68108

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:L/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: 6
  Paranoid ActionableScore: 8

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).