[CVE-2026-72387][MODERATE REGULAR] drm/panthor: Fix potential invalid pointer deref in group_process_tiler_oom() [ Upstream

[CVE-2026-72387][MODERATE REGULAR] drm/panthor: Fix potential invalid pointer deref in group_process_tiler_oom() [ Upstream

[AL-KERNEL]

CVE: CVE-2026-72387
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: drm/panthor: Fix potential invalid pointer deref in group_process_tiler_oom() [ Upstream
Commit: bfc5b91ab3ddddf636d8c1c050455bf4e14c912b
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=bfc5b91ab3ddddf636d8c1c050455bf4e14c912b
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72387
Analysis date: Sat, 15 Aug 2026 14:45:35 -0400
ActionableScore: 3
ActionableScore lower bound: 2
Actionable bucket: Borderline Moderate, manual review recommended
Manual review required: YES

Summary:
A local process with access to an affected Panthor DRM render node may trigger an invalid `ERR_PTR()` dereference in `group_process_tiler_oom()`, causing a kernel crash without evidence of confidentiality, integrity, or privilege escalation impact.

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

The original Linux kernel CVE announcement for CVE-2026-72387 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72387

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-2026-72387	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-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 'An invalid pointer dereference can occur in the Panthor DRM scheduler path when group_process_tiler_oom() observes heaps as ERR_PTR() but later cleanup can still pass that value to panthor_heap_pool_put(). A local process that can submit work to the affected Panthor DRM device may be able to reach the tiler OOM handling path and crash the kernel. For the CVSS the PR:L is used for the paranoid score because access to a local DRM render node or equivalent GPU device context is required, but full administrator privileges are not necessarily required in typical desktop or graphics workloads. The issue is not network reachable and does not indicate a UAF, OOB write, or arbitrary write primitive. Impact is denial of service via kernel crash only.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline Moderate, manual review recommended (with actual score 3)  SKIP CVE-2026-72387 UNKNOWN SKIP No affected files built, so skip this CVE NO  - - unknown 	MAYBE	SIMPLEFIX HARDWARE  INCREASED_FROM_LOW_BASED_ON_REQUIREMANUALCHECK DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN5	-	-	checked

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

ActionableScore=3
ActionableScoreLower=2

## 1. ActionableScore

* Conservative score: 2
* Paranoid score: 3
* Final recommended bucket: **Borderline Moderate, manual review recommended**::

## 2. Signal breakdown

Conservative signals:

* Local unprivileged trigger: +1. A local process with access to the Panthor DRM render node may be able to submit GPU work that reaches the tiler OOM path.
* Reliable kernel crash / strong DoS: +1. The commit explicitly states that `panthor_heap_pool_put()` may dereference an `ERR_PTR()`, which is a credible kernel Oops / crash condition.
* Weak corruption / invalid pointer dereference: +0. This is an invalid pointer dereference, not a demonstrated UAF, OOB write, arbitrary write, type confusion, or attacker-controlled object reuse.

Paranoid additional signal:

* Broad/default local device exposure on affected systems: +1. On systems with Panthor hardware, DRM render nodes may be exposed to ordinary local users or containers for GPU workloads.

Not awarded:

* No remote/network trigger.
* No privilege escalation signal.
* No generic strong memory corruption signal.
* No confidentiality or integrity impact.
* No high-control API bonus, because the patch does not show attacker control over object lifetime, reclaim, callbacks, refcounts, DMA mappings, or page ownership.

## 3. Reachability analysis

The likely trigger is a local process able to access the affected Panthor DRM device and submit GPU work that causes the tiler OOM handling path to run. Full administrator privileges are not necessarily required if `/dev/dri/renderD*` is accessible to users, which is common for graphics workloads.

Containers can matter if the render node is passed through into the container. In that case, a containerized process may reach the host kernel driver through the device node. If the device node is not exposed, the bug is not reachable from that container.

The path is not network reachable. It is hardware and driver dependent, requiring an affected Panthor GPU and the corresponding kernel driver path.

Call-site confidence: medium. The patch shows the immediate invalid cleanup condition, but not the full workload path needed to make `heaps` become `ERR_PTR()`.

## 4. Severity interpretation

This behaves like an ordinary to borderline Moderate local DoS issue, not an Important-class vulnerability. The realistic impact is kernel crash through invalid pointer dereference.

Theoretical memory corruption potential is weak because `ERR_PTR()` dereference normally leads to an invalid address fault rather than controlled memory corruption. The patch does not support UAF reclaim, object replacement, type confusion, writable stale access, arbitrary write, or privilege escalation.

## 5. One-sentence report phrase

A local process with access to an affected Panthor DRM render node may trigger an invalid `ERR_PTR()` dereference in `group_process_tiler_oom()`, causing a kernel crash without evidence of confidentiality, integrity, or privilege escalation impact.

## 6. Manual review recommendation

MANUAL CHECK RECOMMENDED

Reason: this is not an Important candidate based on the patch, but local DRM render-node reachability can be product-dependent and may include container pass-through cases, so it should not be blindly auto-closed without checking device exposure on affected systems.

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

Patch: drm/panthor: Fix potential invalid pointer deref in group_process_tiler_oom() [ Upstream
Commit: bfc5b91ab3ddddf636d8c1c050455bf4e14c912b
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=bfc5b91ab3ddddf636d8c1c050455bf4e14c912b

Changed files:
  drivers/gpu/drm/panthor/panthor_sched.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=bfc5b91ab3ddddf636d8c1c050455bf4e14c912b

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

The original Linux kernel CVE announcement for CVE-2026-72387 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72387

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: 3

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).