[CVE-2026-72327][LOW] drm/v3d: Reject invalid indirect BO handle in indirect CSD setup [ Upstream commit 2f8b8593c7832fad655290cef9e99af05b1b52b3 ]

[AL-KERNEL <alkernel@kernelcve.org>]

CVE: CVE-2026-72327
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: drm/v3d: Reject invalid indirect BO handle in indirect CSD setup [ Upstream commit 2f8b8593c7832fad655290cef9e99af05b1b52b3 ]
Commit: 7c27f630dc78b673e136cab7d410399a1c52146a
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=7c27f630dc78b673e136cab7d410399a1c52146a
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72327
Analysis date: Sat, 15 Aug 2026 17:56:21 -0400
ActionableScore: 2
ActionableScore lower bound: unknown
Actionable bucket: Ordinary Moderate / Low-like
Manual review required: NO

Summary:
A local user with access to the V3D DRM device can submit an invalid indirect BO handle that is stored without a NULL check and later dereferenced during indirect CSD execution, causing a kernel crash DoS.

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

The original Linux kernel CVE announcement for CVE-2026-72327 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72327

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.

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AL-KERNEL CLASSIFICATION RESULT
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CVE-2026-72327	LOW	CHECK WITH IMPACT FROM ORIG NN MODERATE	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-20;CWE-754;BEST CVSS score: '5.5';DESCR 'A NULL pointer dereference in the drm v3d indirect CSD setup path can occur because v3d_get_cpu_indirect_csd_params looks up a userspace supplied indirect BO handle and stores the result without checking for NULL. A local user with access to the V3D DRM device can submit a bogus or stale handle, causing drm_gem_object_lookup to return NULL and allowing the later indirect CSD job path to dereference it in kernel context. For the CVSS the PR:L is used because triggering requires local code execution and access to the DRM device node, but normally does not require full administrator privileges. The issue is not network reachable and is triggered through the local GPU submission interface. Impact is denial of service via kernel crash. No confidentiality or integrity impact is assigned because the patch indicates a NULL dereference rather than a UAF, OOB access, or writable memory corruption primitive.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 2)  SKIP CVE-2026-72327 UNKNOWN SKIP No affected files built, so skip this CVE NO  - - unknown 	MAYBE	NULLPTR SIMPLEFIX HARDWARE LINUS  DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3	-	-	checked

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ACTIONABLESCORE ANALYSIS
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ActionableScore=2

## 1. ActionableScore

* Conservative score: **2**
* Paranoid score: **2**
* Final recommended bucket: **Ordinary Moderate / Low-like**

## 2. Signal breakdown

* **Local unprivileged trigger: +1**
  A local user with access to the V3D DRM device node can submit a bogus or stale userspace BO handle.

* **Reliable kernel crash / strong DoS: +1**
  The unchecked `drm_gem_object_lookup()` result can be stored as `info->indirect` and later dereferenced, producing a kernel NULL pointer dereference.

* **Generic memory corruption: +0**
  The primitive is a NULL pointer dereference, not UAF, double-free, OOB write, type confusion, refcount misuse, or controlled overwrite.

* **Weak LPE concern: +0**
  There is no evidence of attacker-controlled reclaim, stale object reuse, callback control, writable corruption, or object confusion.

* **Confidentiality impact plausible: +0**
  No info leak or read-back path is indicated.

* **Integrity impact plausible: +0**
  No write primitive or policy bypass is indicated.

* **Availability impact realistic: +0 additional**
  Availability is already counted through the reliable kernel crash signal. No persistent corruption or broader system state damage is shown.

## 3. Reachability analysis

The bug is reachable through the local DRM/V3D submission interface by passing an invalid indirect BO handle. In typical systems where the V3D render node is exposed to local users, this is best treated as **PR:L** rather than PR:H. It is not network reachable. Containers or sandboxes may matter only if they are granted access to the relevant `/dev/dri` node. The affected path is hardware and driver specific to V3D, so exposure is narrower than generic DRM or core kernel interfaces.

Call-site confidence: **high**, because the patch and commit message directly identify the lookup result, the stored NULL pointer, and the later dereference during indirect CSD job execution.

## 4. Severity interpretation

This behaves like an **ordinary Moderate local DoS**, not an Important-class vulnerability. The realistic impact is a kernel crash caused by a NULL pointer dereference. Theoretical escalation is not supported by the patch because the bug does not expose a UAF, controlled memory corruption, arbitrary write, page-cache corruption, or security-boundary bypass.

## 5. One-sentence report phrase

A local user with access to the V3D DRM device can submit an invalid indirect BO handle that is stored without a NULL check and later dereferenced during indirect CSD execution, causing a kernel crash DoS.

## 6. Manual review recommendation

**NO MANUAL CHECK NEEDED**

This can be auto-closed for escalation triage because it is a straightforward local NULL pointer dereference with no supported memory-corruption or privilege-escalation primitive.

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

Patch: drm/v3d: Reject invalid indirect BO handle in indirect CSD setup [ Upstream commit 2f8b8593c7832fad655290cef9e99af05b1b52b3 ]
Commit: 7c27f630dc78b673e136cab7d410399a1c52146a
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=7c27f630dc78b673e136cab7d410399a1c52146a

Commit description:

v3d_get_cpu_indirect_csd_params() looks up the indirect buffer object
from a userspace-supplied handle but never checks the result. A bogus
or stale handle makes drm_gem_object_lookup() return NULL, which is
then stored in info->indirect and only dereferenced later when the
indirect CSD job runs, turning a userspace mistake into a NULL pointer
dereference in the kernel.

Bail out with -ENOENT as soon as the lookup fails, so the bad handle is
rejected at submission time.

Fixes: 18b8413b25b7 ("drm/v3d: Create a CPU job extension for a indirect CSD job")
Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>
Signed-off-by: Maíra Canal <mcanal@igalia.com>
Link: https://patch.msgid.link/20260703-v3d-cpu-job-fixes-v3-2-bc51b1f3eeb5@igalia.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat -rw-r--r-- drivers/gpu/drm/v3d/v3d_submit.c 2

Changed files:
  drivers/gpu/drm/v3d/v3d_submit.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=7c27f630dc78b673e136cab7d410399a1c52146a

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

The original Linux kernel CVE announcement for CVE-2026-72327 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72327

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: Not available
  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).