[CVE-2026-68112][MODERATE REGULAR] drm/amdgpu/gfx9.4.3: replace BUG_ON() with WARN_ON()

[CVE-2026-68112][MODERATE REGULAR] drm/amdgpu/gfx9.4.3: replace BUG_ON() with WARN_ON()

[AL-KERNEL]

CVE: CVE-2026-68112
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: drm/amdgpu/gfx9.4.3: replace BUG_ON() with WARN_ON()
Commit: c59b57c2e0c8cced4350ff7792361ba2a79ee85c
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=c59b57c2e0c8cced4350ff7792361ba2a79ee85c
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68112
Analysis date: Mon, 10 Aug 2026 18:49:58 -0400
ActionableScore: 4
ActionableScore lower bound: 2
Actionable bucket: Borderline Moderate / manual triggerability review recommended
Manual review required: NO

Summary:
A reachable BUG_ON in the AMDGPU gfx9.4.3 ring emission path can convert invalid GPU command or fence parameters into a local kernel panic, but the patch does not show memory corruption or privilege escalation beyond denial of service.

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

The original Linux kernel CVE announcement for CVE-2026-68112 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68112

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.

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

CVE-2026-68112	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:N/I:N/A:H';CWE-617;CWE-754;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 'A reachable BUG_ON in the amdgpu gfx9.4.3 ring emission path could turn invalid or misaligned GPU ring parameters into a full kernel panic. The affected checks cover command packet addresses and fence parameters used while emitting WAIT_REG_MEM, INDIRECT_BUFFER, and fence write packets. For the CVSS the PR:L is used because a local process with access to the DRM GPU device or render node may be sufficient in some deployments, although reliable triggering still depends on whether user controlled command submission can reach these exact invalid states. The issue is not network reachable and requires local interaction with the GPU driver control path. Impact is denial of service via kernel crash only. No concrete memory corruption, information leak, or privilege escalation primitive is visible from the patch context.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline Moderate / manual triggerability review recommended (with actual score 3)  SKIP CVE-2026-68112 UNKNOWN SKIP No affected files built, so skip this CVE NO  - - unknown 	MAYBE	OOB DANGER SIMPLEFIX KERNEL_PANIC_PLUS_UAF HARDWARE PACKET  DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH	-	-	checked

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

ActionableScore=4
ActionableScoreLower=2

## 1. ActionableScore

* Conservative score: 2
* Paranoid score: 4
* Final recommended bucket: **Borderline Moderate / manual triggerability review recommended**::

## 2. Signal breakdown

Conservative signals:

* Local unprivileged trigger: +1
  A local process with access to the AMD GPU DRM device or render node may be able to reach amdgpu command submission paths, but the exact user-controlled path to these invalid alignment or flag states is not proven by the patch.

* Reliable kernel crash / strong DoS: +1
  The original code used BUG_ON(), so if the condition is reachable, the result is an intentional kernel panic.

* Broad/default/common subsystem or broadly deployed exposure: +1
  DRM render nodes are commonly exposed to local users on GPU systems, although this specific code is limited to AMD gfx9.4.3 hardware.

* Hard or unreliable trigger / special condition required: -1
  The patch does not show that userspace can directly control addr0, ib->gpu_addr, fence addr, or KIQ fence flags in a way that reliably violates these invariants.

Paranoid additional interpretation:

* Availability impact realistic: +1
  If reachable through ordinary DRM access, the impact is host-wide kernel panic, not just a local process failure.

No score awarded for:

* Generic memory corruption: +0
  The patch shows reachable assertions, not UAF, OOB write, type confusion, arbitrary write, or refcount misuse.

* Privilege escalation plausible: +0
  No concrete LPE primitive is visible.

* Confidentiality or integrity impact: +0
  No leak, unauthorized write, or cross-boundary corruption is supported by the patch.

## 3. Reachability analysis

The plausible attacker is a local user or process that can access the AMD GPU through DRM device nodes. In many desktop or compute deployments, render nodes may be accessible to non-root users through group permissions or seat management. However, the patch does not prove that normal command submission can produce the misaligned GPU addresses or invalid fence flags needed to hit the old BUG_ON() checks.

Namespaces and containers may matter if GPU devices are passed through or exposed to a container. A container user with access to `/dev/dri/renderD*` could potentially have the same practical trigger surface as a host user, but this depends on device delegation.

The path is not network reachable. It is hardware and driver specific to AMD gfx9.4.3. The realistic exploitation condition is local GPU driver access plus a reachable path to violate the checked ring emission invariants.

Call-site confidence: medium. The changed functions are visible and clearly in GPU ring emission paths, but the patch does not include the higher-level user submission call chain proving direct user control over the invalid values.

## 4. Severity interpretation

This behaves more like an ordinary-to-borderline Moderate local DoS than an Important-class vulnerability. The strongest demonstrated impact is kernel panic through reachable BUG_ON() assertions. The theoretical concern is that local unprivileged GPU access could make the panic easy to trigger, but there is no evidence of memory corruption, privilege escalation, information disclosure, or arbitrary kernel state manipulation.

The paranoid score is higher only because DRM render nodes are often available to local users and a reachable BUG_ON() is a host-wide crash. It should not be escalated to Important without proof that userspace can reliably control the affected parameters or that continued execution after the WARN_ON() exposes a separate corruption primitive.

## 5. One-sentence report phrase

A reachable BUG_ON in the AMDGPU gfx9.4.3 ring emission path can convert invalid GPU command or fence parameters into a local kernel panic, but the patch does not show memory corruption or privilege escalation beyond denial of service.

## 6. Manual review recommendation

MANUAL CHECK RECOMMENDED

YES REQUIRES MANUAL CHECK for environments exposing AMD GPU render nodes to untrusted local users, because practical severity depends on whether userspace command submission can reliably reach the invalid alignment or flag states.

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

Patch: drm/amdgpu/gfx9.4.3: replace BUG_ON() with WARN_ON()
Commit: c59b57c2e0c8cced4350ff7792361ba2a79ee85c
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=c59b57c2e0c8cced4350ff7792361ba2a79ee85c

Commit description:

There's no need to crash the kernel for these cases.

Reviewed-by: Vitaly Prosyak <vitaly.prosyak@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 5676593 )
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Changed files:
  drivers/gpu/drm/amd/amdgpu/gfx_v9_4_3.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=c59b57c2e0c8cced4350ff7792361ba2a79ee85c

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

The original Linux kernel CVE announcement for CVE-2026-68112 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68112

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: 2
  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).