[CVE-2026-43320][LOW] drm/amd/display: Fix dsc eDP issue [ Upstream

[CVE-2026-43320][LOW] drm/amd/display: Fix dsc eDP issue [ Upstream

[AL-KERNEL]

CVE: CVE-2026-43320
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: drm/amd/display: Fix dsc eDP issue [ Upstream
Commit: 11718976c53a258c4d107aa05d68773379d0006f
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=11718976c53a258c4d107aa05d68773379d0006f
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-43320
Analysis date: Sat, 01 Aug 2026 12:33:04 -0400
ActionableScore: 2
ActionableScore lower bound: unknown
Actionable bucket: Ordinary Moderate / Low-like, auto-close candidate
Manual review required: YES

Summary:
A local NULL function pointer dereference in the AMD display DSC cleanup path may allow a user with DRM display control access to crash the kernel on affected eDP DSC configurations, with no evidence of privilege escalation or data disclosure.

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

The original Linux kernel CVE announcement for CVE-2026-43320 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-43320

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: LOW
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
======================================================================

CVE-2026-43320	LOW	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-476;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 NULL function pointer dereference may occur in the AMD display DSC cleanup path because several DSC related function hooks can be called without checking whether the callbacks exist for the current hardware and eDP configuration. A local user may be able to reach this path through DRM display control, modeset, suspend resume, hotplug, or display reconfiguration on affected AMD GPU systems. For the CVSS the PR:L is used because practical triggering may be possible from a local graphical session or another process with delegated DRM device access, even if full administrative privileges are not required in that environment. The issue is not network reachable and requires local interaction with display control paths on affected hardware. Impact is denial of service via kernel crash. No UAF, OOB write, arbitrary write, or information leak primitive is indicated by the patch context, so confidentiality and integrity remain N even for the paranoid score.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like, auto-close candidate (with actual score 2)  SKIP CVE-2026-43320  SKIP No affected files built, so skip this CVE NO  - - unknown 	MAYBE	HARDWARE  INCREASED_FROM_LOW_BASED_ON_HIGHCVSSSCORE DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN5 DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3	-	-	checked

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

ActionableScore=2

## 1. ActionableScore

* Conservative score: 2
* Paranoid score: 2
* Final recommended bucket: **Ordinary Moderate / Low-like, auto-close candidate**

## 2. Signal breakdown

Triggered signals:

* Local unprivileged trigger: +1
  A local graphical user or process with delegated DRM/KMS access may be able to trigger display reconfiguration, modeset, hotplug, suspend/resume, or eDP DSC cleanup paths.

* Reliable kernel crash / strong DoS: +1
  The patch prevents calls through potentially NULL DSC callback hooks. If reached, this is a NULL function pointer dereference and likely kernel Oops or panic depending system policy.

Not triggered:

* Remote reachable: +0
  No network path is involved.

* Generic memory corruption: +0
  This is a NULL callback dereference, not UAF, OOB write, double free, refcount corruption, arbitrary write, or type confusion.

* Privilege escalation plausible: +0
  No attacker-controlled function pointer, reclaim primitive, write primitive, or object confusion is indicated.

* Confidentiality / Integrity impact: +0
  No leak or modification primitive is visible.

* Rare hardware/config penalty: 0
  The exact trigger depends on affected AMD display hardware and eDP DSC configuration, but DRM display paths are ordinary local interfaces on affected systems, so I would not apply a strong rarity penalty.

Call-site confidence: high. The changed call sites directly show unchecked callback invocation before the fix.

## 3. Reachability analysis

The bug is local-only. It may be reachable by a local user with access to DRM display control paths, especially in desktop or workstation environments where the active graphical session has modeset/display-management capabilities. It is not remotely reachable and does not appear triggerable through packet processing or another network-facing path.

Namespaces and containers usually do not increase exposure unless the container is explicitly given access to the host DRM device. In typical deployments, the issue is limited to systems with affected AMD display hardware and an eDP DSC-related path.

## 4. Severity interpretation

This behaves like an ordinary Moderate or Low-like kernel DoS issue. The theoretical failure mode is a NULL function pointer dereference in a GPU display cleanup path, but the patch does not show a memory corruption primitive useful for privilege escalation. Realistic impact is availability only, via local kernel crash or display subsystem failure.

## 5. One-sentence report phrase

A local NULL function pointer dereference in the AMD display DSC cleanup path may allow a user with DRM display control access to crash the kernel on affected eDP DSC configurations, with no evidence of privilege escalation or data disclosure.

## 6. Manual review recommendation

NO MANUAL CHECK NEEDED

This can be handled as NO MANUAL CHECK REQUIRED COULD BE AUTOCLOSED because the patch only adds missing callback existence checks, the impact is DoS-only, and no memory corruption or security-boundary bypass primitive is supported by the diff.

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

Patch: drm/amd/display: Fix dsc eDP issue [ Upstream
Commit: 11718976c53a258c4d107aa05d68773379d0006f
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=11718976c53a258c4d107aa05d68773379d0006f

Changed files:
  drivers/gpu/drm/amd/display/dc/hwss/dce110/dce110_hwseq.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=11718976c53a258c4d107aa05d68773379d0006f

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

The original Linux kernel CVE announcement for CVE-2026-43320 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-43320

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: unknown
  Paranoid ActionableScore: 2

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: LOW
KPANIC detected for this report: NO
Published priority for this report (same as in Subject): LOW

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).