[CVE-2026-53315][LOW] drm/amd/ras: Fix NULL deref in ras_core_get_utc_second_timestamp() [ Upstream

[CVE-2026-53315][LOW] drm/amd/ras: Fix NULL deref in ras_core_get_utc_second_timestamp() [ Upstream

[AL-KERNEL]

CVE: CVE-2026-53315
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: drm/amd/ras: Fix NULL deref in ras_core_get_utc_second_timestamp() [ Upstream
Commit: 6c84f7f0afc415691ffa7d48aa7ce1d8e6083032
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=6c84f7f0afc415691ffa7d48aa7ce1d8e6083032
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53315
Analysis date: Fri, 26 Jun 2026 15:43:45 -0400
ActionableScore: 1
ActionableScore lower bound: 0
Actionable bucket: Ordinary Moderate / Low-like
Manual review required: NO

Summary:
A NULL pointer dereference in the AMDGPU RAS timestamp path can crash the kernel if `ras_core_get_utc_second_timestamp()` is reached with a NULL `ras_core`, but practical triggering appears limited to local or device-management contexts and does not indicate LPE or data exposure.

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

The original Linux kernel CVE announcement for CVE-2026-53315 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53315

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: NO

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

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

CVE-2026-53315	LOW	CHECK	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H';**CWE-476;CWE-703;CWE-754;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '4.7';DESCR 'A NULL pointer dereference in the AMDGPU RAS timestamp path can occur when ras_core_get_utc_second_timestamp is called with ras_core equal to NULL. The previous control flow checked ras_core before using the platform callback, but the failure path still logged through ras_core dev, which would dereference a NULL pointer and can crash the kernel. For the CVSS the PR:L is used in the paranoid score only if a local user can indirectly trigger RAS event handling through delegated GPU access or reduced capability administration. In the normal deployment PR:H is more realistic because RAS injection, driver reset, or low level GPU management is usually administrator controlled. The issue is not network reachable. Impact is denial of service via kernel crash only, with no supported path to information disclosure or privilege escalation.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 1)  SKIP CVE-2026-53315  SKIP No affected files built, so skip this CVE NO  - - unknown 	MAYBE	NULLPTR SIMPLEFIX HARDWARE  DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_GUESSCVSS_AND_CIANNH	-	-	checked

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

ActionableScore=1
ActionableScoreLower=0

## 1. ActionableScore

* Conservative score: 0
* Paranoid score: 1
* Final recommended bucket: **Ordinary Moderate / Low-like**

## 2. Signal breakdown

Triggered signals:

* Reliable kernel crash / strong DoS: +1
  The patch prevents a NULL pointer dereference in `ras_core_get_utc_second_timestamp()` when `ras_core == NULL`.

Subtracted or not awarded:

* Requires admin/root/device-management access in typical deployments: -2
  Realistic triggering likely requires AMDGPU RAS handling, reset, error injection, firmware/device error paths, or low-level GPU management.

* Rare or hardware-specific path: -1
  The affected path is AMDGPU RAS timestamping, not a broad default kernel interface.

* No generic memory corruption: +0
  This is a NULL dereference, not UAF, OOB write, double free, type confusion, refcount misuse, or arbitrary write.

* No LPE signal: +0
  The patch does not show stale object reuse, attacker-controlled reclaim, callback corruption, or writable corruption.

* No confidentiality or integrity impact: +0
  There is no supported read-back, info leak, file corruption, credential exposure, or privilege boundary bypass.

Paranoid score keeps +1 for possible local/device-mediated DoS but does not elevate beyond that.

## 3. Reachability analysis

The bug is reachable only if `ras_core_get_utc_second_timestamp()` is called with a NULL `ras_core`. In normal operation this is an internal AMDGPU RAS path, not a direct syscall, network protocol, or common unprivileged API. A local unprivileged user is not clearly able to trigger it reliably. Containers or namespaces do not meaningfully lower the privilege requirement unless GPU management or RAS controls are explicitly delegated. The path is hardware and driver specific and depends on AMDGPU RAS behavior.

## 4. Severity interpretation

This behaves like a low-end Moderate or Low-like kernel DoS issue. The realistic impact is a kernel crash through NULL dereference. There is no evidence of practical privilege escalation, information disclosure, or integrity impact. Theoretical concern remains limited because NULL dereference is not a controllable memory corruption primitive.

## 5. One-sentence report phrase

A NULL pointer dereference in the AMDGPU RAS timestamp path can crash the kernel if `ras_core_get_utc_second_timestamp()` is reached with a NULL `ras_core`, but practical triggering appears limited to local or device-management contexts and does not indicate LPE or data exposure.

## 6. Manual review recommendation

NO MANUAL CHECK NEEDED

This can be autoclosure-level triage unless local evidence shows unprivileged users can reliably trigger AMDGPU RAS event handling on affected systems.

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

Patch: drm/amd/ras: Fix NULL deref in ras_core_get_utc_second_timestamp() [ Upstream
Commit: 6c84f7f0afc415691ffa7d48aa7ce1d8e6083032
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=6c84f7f0afc415691ffa7d48aa7ce1d8e6083032

Changed files:
  drivers/gpu/drm/amd/ras/rascore/ras_core.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=6c84f7f0afc415691ffa7d48aa7ce1d8e6083032

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

The original Linux kernel CVE announcement for CVE-2026-53315 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53315

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:H/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS score: 4.7

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: 0
  Paranoid ActionableScore: 1

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).