[CVE-2026-68269][MODERATE REGULAR] drm/i915/gem: Add missing nospec on parallel submit slot

[CVE-2026-68269][MODERATE REGULAR] drm/i915/gem: Add missing nospec on parallel submit slot

[AL-KERNEL]

CVE: CVE-2026-68269
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: drm/i915/gem: Add missing nospec on parallel submit slot
Commit: 4a27275d275971c9ea29d3d240ea4a224ad368a2
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=4a27275d275971c9ea29d3d240ea4a224ad368a2
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68269
Analysis date: Mon, 10 Aug 2026 16:59:58 -0400
ActionableScore: 4
ActionableScore lower bound: 3
Actionable bucket: Borderline / manual review recommended. Not an Important candidate by current evidence
Manual review required: YES

Summary:
No one-sentence report phrase was found.

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

The original Linux kernel CVE announcement for CVE-2026-68269 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68269

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-2026-68269	MODERATE	CHECK WITH IMPACT FROM ORIG NN IMPORTANT	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N';CWE-203;*CWE-200;CWE-125;Other CVSS 'AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N';BEST CVSS score: '4.7';DESCR 'drm/i915 parallel submit context setup uses a userspace controlled slot index to select set engines slot after a bounds check. Without a nospec barrier, Spectre V1 style bounds check bypass can transiently access an out of bounds engines entry and potentially expose data through microarchitectural side channels. For the CVSS the PR:L is used because a local user or process must reach the i915 GEM context UAPI, commonly through a render device, and no administrative privilege is required in typical desktop or GPU compute deployments. The issue is not network reachable and requires local code execution on affected Intel GPU systems. Impact is confidentiality only. There is no evidence of memory corruption, privilege escalation, or availability impact from the patch context.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline / manual review recommended. Not an Important candidate by current evidence (with actual score 4)  SKIP CVE-2026-68269 UNKNOWN SKIP No affected files built, so skip this CVE NO  - - unknown 	MAYBE	SIMPLEFIX SPECTRE HARDWARE 	-	-	checked

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

ActionableScore=4
ActionableScoreLower=3

1. ActionableScore
* Conservative score: 3
* Paranoid score: 4
* Final recommended bucket: **Borderline / manual review recommended. Not an Important candidate by current evidence**

2. Signal breakdown
* Local unprivileged trigger: +1. The affected path is an i915 GEM context UAPI reachable by a local process with access to the GPU render device.
* Confidentiality impact plausible: +1. The missing `array_index_nospec()` creates a Spectre V1 style bounds-check bypass gadget with possible transient out-of-bounds data exposure.
* Broad/default/common subsystem exposure: +1. Intel i915 render devices are common on desktop, workstation, and GPU compute systems, although exposure depends on local device permissions.
* Practical exploit chain strongly implied: +1 for paranoid score only. The commit explicitly says this is a missing Spectre mitigation for a userspace controlled slot and was confirmed by Intel Product Security, but no complete disclosure exploit is shown.
* No generic memory corruption. This is transient speculative access, not architectural OOB read/write, UAF, double free, or heap corruption.
* No privilege escalation signal. The patch does not show write capability, object lifetime corruption, callback control, or credential impact.
* No reliable DoS signal. No crash, panic, hang, or availability failure is described.

3. Reachability analysis
A local user or local process can potentially trigger the issue if it can access the i915 GEM context interface, commonly through a render node such as `/dev/dri/renderD*`. This is not network reachable. Containers may matter if GPU device nodes are passed through to the container, because a containerized process with render-node access could reach the same UAPI without host root. The path is common on Intel GPU systems but not universal, and practical exploitation depends on CPU speculation behavior, local timing side channels, kernel and userspace mitigations, and whether useful adjacent data can be inferred.

Call-site confidence: medium. The patch gives the affected function and exact indexed access, but not the full surrounding call graph or data layout.

4. Severity interpretation
This behaves more like an actionable low-to-moderate confidentiality issue than an Important kernel vulnerability. The theoretical issue is a Spectre V1 style transient information disclosure gadget, not memory corruption. Realistic exploitation evidence is limited by the lack of a demonstrated leak target or end-to-end exploit path, but Intel Product Security confirmation and the explicit userspace-controlled index make it unsuitable for automatic closure without review.

5. One-sentence report phrase
A missing `array_index_nospec()` in the i915 parallel submit context path allows a local user with i915 GEM access to potentially trigger a Spectre V1 style transient out-of-bounds read, causing possible local confidentiality impact but no demonstrated integrity, availability, or privilege-escalation impact.

6. Manual review recommendation
MANUAL CHECK RECOMMENDED.
The issue is security-confirmed and affects a userspace-controlled GPU UAPI, but current evidence supports only local speculative confidentiality impact, not memory corruption or LPE.

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

Patch: drm/i915/gem: Add missing nospec on parallel submit slot
Commit: 4a27275d275971c9ea29d3d240ea4a224ad368a2
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=4a27275d275971c9ea29d3d240ea4a224ad368a2

Commit description:

Add missing Spectre mitigation for userspace controlled parallel
submission slot.

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

Reported-by: Martin Hodo <martin.hodo@intel.com>
Fixes: e5e3217 ("drm/i915/guc: Connect UAPI to GuC multi-lrc interface")
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Tvrtko Ursulin <tursulin@ursulin.net>
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Cc: <stable@vger.kernel.org> # v5.16+
Link: https://patch.msgid.link/20260622132539.165558-1-joonas.lahtinen@linux.intel.com
(cherry picked from commit 15b9353 )
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.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=4a27275d275971c9ea29d3d240ea4a224ad368a2

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

The original Linux kernel CVE announcement for CVE-2026-68269 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68269

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