[CVE-2026-72091][MODERATE REGULAR] accel/amdxdna: reject user command submission without a command BO commit 261c1fe3327ad24508f54552c6366e3e4db82c15 upstream.

[CVE-2026-72091][MODERATE REGULAR] accel/amdxdna: reject user command submission without a command BO commit 261c1fe3327ad24508f54552c6366e3e4db82c15 upstream.

[AL-KERNEL]

CVE: CVE-2026-72091
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: accel/amdxdna: reject user command submission without a command BO commit 261c1fe3327ad24508f54552c6366e3e4db82c15 upstream.
Commit: fff6509d976f6fae423a5236391ccdbd7e0e9f06
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=fff6509d976f6fae423a5236391ccdbd7e0e9f06
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72091
Analysis date: Sun, 16 Aug 2026 08:59:52 -0400
ActionableScore: 3
ActionableScore lower bound: unknown
Actionable bucket: Borderline Moderate. Manual review recommended, not an Important candidate
Manual review required: YES

Summary:
A local user with access to the amdxdna accel device node can submit AMDXDNA_EXEC_CMD without a command BO, causing a NULL pointer dereference in the DRM scheduler worker and resulting in a kernel oops or local denial of service.

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

The original Linux kernel CVE announcement for CVE-2026-72091 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72091

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-2026-72091	MODERATE	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 amdxdna accel driver can occur when a user submits AMDXDNA_EXEC_CMD with an invalid command BO handle and no internal driver command. This leaves job cmd_bo unset and later the DRM scheduler worker reaches amdxdna_cmd_set_state with a NULL command BO, causing a kernel oops. For the CVSS the PR:L is used because triggering requires a local process with access to the accel device node, commonly through render group or similar device permissions. The issue is not network reachable and requires a system with a probed AMD NPU and the amdxdna driver exposed to the caller. Impact is denial of service via kernel crash. No practical confidentiality or integrity impact is indicated because the primitive is a NULL dereference rather than UAF, OOB access, or controlled memory corruption.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline Moderate. Manual review recommended, not an Important candidate (with actual score 3)  SKIP CVE-2026-72091 UNKNOWN SKIP No affected files built, so skip this CVE NO  - - unknown 	MAYBE	DANGER NULLPTR IMPROVEONLY  DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH	-	-	checked

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

ActionableScore=3

## 1. ActionableScore

* Conservative score: 3
* Paranoid score: 3
* Final recommended bucket: **Borderline Moderate. Manual review recommended, not an Important candidate**::

## 2. Signal breakdown

Triggered signals:

* Local unprivileged trigger: +1
  A local process with access to the accel device node can issue one AMDXDNA_EXEC_CMD ioctl with cmd_handles set to 0.

* Reliable kernel crash / strong DoS: +1
  The commit describes a direct NULL pointer dereference in the drm_sched worker through amdxdna_cmd_set_state(job->cmd_bo) when job->cmd_bo is NULL.

* Availability impact realistic: +1
  The trigger is simple and deterministic on affected systems with a probed AMD NPU and exposed amdxdna accel node. This can cause a kernel oops or crash depending on system policy such as panic_on_oops.

Not awarded:

* No generic memory corruption bonus. The primitive is a NULL pointer dereference, not UAF, OOB write, double free, type confusion, or controlled overwrite.
* No privilege escalation bonus. The patch does not show attacker-controlled reclaim, object replacement, callback control, arbitrary write, or other LPE-relevant primitive.
* No confidentiality or integrity impact. There is no leak or write primitive.
* No remote reachability. The path is a local ioctl on an accel device node.
* No high-control device API bonus. Although this is a DRM accel ioctl, the patch only shows invalid object validation leading to NULL dereference, not attacker control over memory layout, object lifetime, DMA ownership, callbacks, or refcounts.

## 3. Reachability analysis

The bug is reachable by a local process that can open the amdxdna accel node on a system where an AMD NPU is present and the amdxdna driver is probed. In many deployments this may correspond to users in a render or device-access group rather than full root, so PR:L is the appropriate practical interpretation. Containers or sandboxed environments matter only if the accel node is passed through into the container. The path is not network reachable and is not exposed on systems without the relevant AMD NPU device or without user access to the accel node.

## 4. Severity interpretation

This behaves like a local Moderate denial-of-service issue. It is actionable enough for manual review because a low-privileged local user with device-node access can trigger a kernel oops with a single ioctl, but it does not look like an Important-class vulnerability. The theoretical risk is limited by the primitive: the patch shows a NULL dereference from a missing command BO validation check, not memory corruption with attacker-controlled reuse or overwrite. Realistic impact is kernel availability loss, not privilege escalation.

## 5. One-sentence report phrase

A local user with access to the amdxdna accel device node can submit AMDXDNA_EXEC_CMD without a command BO, causing a NULL pointer dereference in the DRM scheduler worker and resulting in a kernel oops or local denial of service.

## 6. Manual review recommendation

MANUAL CHECK RECOMMENDED

Reason: the bug is not memory corruption and does not support LPE based on the patch, but the trigger is simple, local, and may be available to non-root users through device-node permissions on affected AMD NPU systems.

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

Patch: accel/amdxdna: reject user command submission without a command BO commit 261c1fe3327ad24508f54552c6366e3e4db82c15 upstream.
Commit: fff6509d976f6fae423a5236391ccdbd7e0e9f06
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=fff6509d976f6fae423a5236391ccdbd7e0e9f06

Commit description:

amdxdna_drm_submit_execbuf() passes the user-supplied command BO handle
straight into amdxdna_cmd_submit() with drv_cmd == NULL. When the handle
is AMDXDNA_INVALID_BO_HANDLE (0), the block that fetches job->cmd_bo is
skipped, leaving it NULL, and no check rejects it on the user path (the
!job->cmd_bo guard lives inside the != INVALID branch).

The job is then armed and pushed to the DRM scheduler.
aie2_sched_job_run() takes the drv_cmd == NULL path and calls
amdxdna_cmd_set_state(job->cmd_bo) -> amdxdna_gem_vmap(NULL) ->
to_gobj(NULL)->dev, a NULL pointer dereference in the drm_sched worker.
A process with access to the accel node on a system with a probed AMD NPU
can trigger a kernel oops with a single AMDXDNA_EXEC_CMD ioctl
(cmd_handles = 0).

Only internal driver commands (SYNC_DEBUG_BO / ATTACH_DEBUG_BO)
legitimately pass AMDXDNA_INVALID_BO_HANDLE, and they always set drv_cmd.
Reject the invalid handle for user submissions (drv_cmd == NULL) at the
submit choke point so every user path is covered.

Fixes: aac243092b70 ("accel/amdxdna: Add command execution")
Cc: stable@vger.kernel.org
Found by 0sec automated security-research tooling (https://0sec.ai).
Assisted-by: 0sec:claude-opus-4-8
Signed-off-by: Doruk Tan Ozturk <doruk@0sec.ai>
Reviewed-by: Lizhi Hou <lizhi.hou@amd.com>
Signed-off-by: Lizhi Hou <lizhi.hou@amd.com>
Link: https://patch.msgid.link/20260713173030.87541-2-doruk@0sec.ai
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat -rw-r--r-- drivers/accel/amdxdna/amdxdna_ctx.c 10

Changed files:
  drivers/accel/amdxdna/amdxdna_ctx.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=fff6509d976f6fae423a5236391ccdbd7e0e9f06

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

The original Linux kernel CVE announcement for CVE-2026-72091 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72091

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: 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).