[CVE-2026-68243][MODERATE REGULAR] drm/i915/gem: Fix NULL deref in I915_CONTEXT_PARAM_SSEU

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

CVE: CVE-2026-68243
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: drm/i915/gem: Fix NULL deref in I915_CONTEXT_PARAM_SSEU
Commit: edd2edaca52ada833c341c8b264aaea9dd93369c
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=edd2edaca52ada833c341c8b264aaea9dd93369c
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68243
Analysis date: Mon, 10 Aug 2026 16:46:18 -0400
ActionableScore: 4
ActionableScore lower bound: 3
Actionable bucket: Borderline, manual review recommended
Manual review required: YES

Summary:
A local user with access to the i915 DRM device can apply `I915_CONTEXT_PARAM_SSEU` to an invalid engine slot and trigger a NULL pointer dereference, causing a kernel denial of service without evidence of privilege escalation.

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

The original Linux kernel CVE announcement for CVE-2026-68243 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68243

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.

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AL-KERNEL CLASSIFICATION RESULT
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CVE-2026-68243	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-20;CWE-703;BEST CVSS score: '5.5';DESCR 'drm i915 GEM context handling can dereference a NULL engine pointer when I915_CONTEXT_PARAM_SSEU is applied to a user engine slot that was previously set to I915_ENGINE_CLASS_INVALID or I915_ENGINE_CLASS_INVALID_NONE. A local user with access to the i915 DRM device can trigger this through context parameter operations and cause a kernel NULL pointer dereference. For the CVSS the PR:L is used because the attacker needs local access to the DRM device or render node, which is commonly available to logged in users or users in the render or video group. The issue is not network reachable. Impact is denial of service via kernel oops or crash. There is no supported evidence for information disclosure or privilege escalation because the primitive is a NULL pointer dereference rather than UAF, OOB access, or arbitrary write.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline, manual review recommended (with actual score 4)  SKIP CVE-2026-68243 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
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ActionableScore=4
ActionableScoreLower=3

## 1. ActionableScore

* Conservative score: 3
* Paranoid score: 4
* Final recommended bucket: **Borderline, manual review recommended**::

## 2. Signal breakdown

Triggered signals:

* Local unprivileged trigger: +1
  The bug is reachable through i915 GEM context parameter handling. On many desktop and GPU compute systems, `/dev/dri/renderD*` is accessible to logged-in users or users in the `render` or `video` group.

* Reliable kernel crash / strong DoS: +1
  The commit explicitly describes a NULL dereference when `I915_CONTEXT_PARAM_SSEU` is applied to an invalid engine slot. This is a concrete crash primitive, not only a warning.

* Broad/default/common subsystem or broadly deployed exposure: +1
  i915 is widely deployed on Intel GPU systems, and DRM render nodes are commonly exposed to non-root local users.

Paranoid-only signal:

* Availability impact realistic: +1
  The trigger appears simple once DRM access is available. Depending on kernel configuration, a NULL dereference may cause an oops, service disruption, or full panic with `panic_on_oops`.

Not applied:

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

* Privilege escalation plausible: +0
  No reclaim, stale object reuse, write primitive, callback dispatch, or object confusion is shown.

* High-control kernel data-plane API: +0
  DRM object configuration alone is not enough for this bonus under the provided rules.

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

Call-site confidence: high for the NULL dereference condition. Medium for deployment reachability because device-node permissions vary by distribution and product profile.

## 3. Reachability analysis

A local user who can open the i915 DRM device can set a context engine slot to `I915_ENGINE_CLASS_INVALID` or `I915_ENGINE_CLASS_INVALID_NONE`, then apply `I915_CONTEXT_PARAM_SSEU` to the same slot. The old code dereferenced `pe->engine->class` without checking whether `pe->engine` was NULL.

This does not require CAP_SYS_ADMIN in typical desktop-style DRM render-node deployments, but some server or locked-down systems may restrict DRM device access. Containers may inherit access if the render node is passed through, but there is no namespace-specific bypass shown.

The path is not network reachable. Realistic exploitation is local DoS only unless the environment exposes the GPU device to sandboxed or containerized workloads where crashing the host kernel has higher operational impact.

## 4. Severity interpretation

This behaves like a borderline actionable Moderate issue, not an Important-class vulnerability.

Theoretical memory-corruption potential is low because the patch supports only a NULL pointer dereference. There is no evidence of UAF, OOB access, arbitrary write, stale callback, refcount manipulation, or attacker-controlled object replacement. Realistic exploitation evidence supports local denial of service through a kernel oops or crash.

The issue should not be treated as Low automatically because it is a simple local trigger in a commonly exposed GPU driver path. It also should not be escalated to Important because no privilege escalation or confidentiality/integrity primitive is supported by the patch.

## 5. One-sentence report phrase

A local user with access to the i915 DRM device can apply `I915_CONTEXT_PARAM_SSEU` to an invalid engine slot and trigger a NULL pointer dereference, causing a kernel denial of service without evidence of privilege escalation.

## 6. Manual review recommendation

MANUAL CHECK RECOMMENDED

Reason: the bug is a local low-privilege kernel crash in a commonly exposed DRM path, but the primitive is only NULL dereference and does not currently justify Important-class handling.

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

Patch: drm/i915/gem: Fix NULL deref in I915_CONTEXT_PARAM_SSEU
Commit: edd2edaca52ada833c341c8b264aaea9dd93369c
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=edd2edaca52ada833c341c8b264aaea9dd93369c

Commit description:

Setting context engine slot N into I915_ENGINE_CLASS_INVALID /
I915_ENGINE_CLASS_INVALID_NONE and attempting to apply
I915_CONTEXT_PARAM_SSEU to the same slot N will deref NULL.
Fix that.

Discovered using AI-assisted static analysis confirmed by
Intel Product Security.

Reported-by: Martin Hodo <martin.hodo@intel.com>
Fixes: d4433c7 ("drm/i915/gem: Use the proto-context to handle create parameters (v5)")
Cc: Faith Ekstrand <faith.ekstrand@collabora.com>
Cc: Simona Vetter <simona.vetter@ffwll.ch>
Cc: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: <stable@vger.kernel.org> # v5.15+
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
Link: https://patch.msgid.link/20260701075555.52142-1-joonas.lahtinen@linux.intel.com
(cherry picked from commit 36eda5b )
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Changed files:
  drivers/gpu/drm/i915/gem/i915_gem_context.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=edd2edaca52ada833c341c8b264aaea9dd93369c

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

The original Linux kernel CVE announcement for CVE-2026-68243 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68243

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: 3
  Paranoid ActionableScore: 4

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).