[CVE-2026-68247][MODERATE 7.0] drm/i915/bios: range check LFP Data Block panel_type2

[CVE-2026-68247][MODERATE 7.0] drm/i915/bios: range check LFP Data Block panel_type2

[AL-KERNEL]

CVE: CVE-2026-68247
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: drm/i915/bios: range check LFP Data Block panel_type2
Commit: e7b5694645b03e80830dc141b59fc65aac693c70
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=e7b5694645b03e80830dc141b59fc65aac693c70
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68247
Analysis date: Mon, 10 Aug 2026 17:14:12 -0400
ActionableScore: 5
ActionableScore lower bound: 3
Actionable bucket: Actionable Moderate at minimum
Manual review required: NO

Summary:
An unchecked `panel_type2` value in i915 VBT parsing can allow malformed firmware-supplied display metadata to select an invalid LFP2 panel type, plausibly causing limited out-of-bounds table access or display initialization DoS, with typical exploitation requiring firmware or platform-data control.

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ABOUT THIS REPORT
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The original Linux kernel CVE announcement for CVE-2026-68247 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68247

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 7.0
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-2026-68247	MODERATE	CHECK WITH IMPACT FROM ORIG NN LOW	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:H';*CWE-20;CWE-129;CWE-125;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:L/I:N/A:L';BEST CVSS score: '5.8';DESCR 'i915 VBT parsing did not range check LFP Data Block panel_type2 while panel_type was already validated. A malformed or attacker controlled VBT could make the driver select an invalid LFP2 panel type and later use it as a panel table selector, which can plausibly lead to incorrect table access, an out-of-bounds read, or display initialization failure. For the CVSS the PR:L is used in the paranoid score to cover environments where a reduced-privilege local actor or service can influence firmware supplied display tables, virtual platform data, or device configuration used by the driver. In typical bare metal systems the practical requirement is closer to PR:H because modifying VBT or firmware data normally requires administrative or firmware level control. The issue is not network reachable. Impact is mainly local denial of service or limited confidentiality exposure from invalid table reads, with integrity impact kept low because the patch does not show a write primitive.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Actionable Moderate at minimum (with actual score 4)  SKIP CVE-2026-68247 UNKNOWN SKIP The Fixes patch not applied yet, so unlikely that actual: 6434cf630086eea2d091f122f5802582a05d9d1c YES  NO NO unknown 	MAYBE	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=5
ActionableScoreLower=3

## 1. ActionableScore

* Conservative score: 3
* Paranoid score: 5
* Final recommended bucket: **Actionable Moderate at minimum**::

## 2. Signal breakdown

Conservative signals:

* Firmware-mediated external influence: +1
  The invalid `panel_type2` value comes from VBT / BIOS display metadata, not from normal packet or syscall input.
* Memory corruption, weak/indirect corruption candidate: +1
  The bug is an unchecked panel type selector. It may cause invalid table selection or limited out-of-bounds reads, but the patch does not show an OOB write, UAF, reclaim, or arbitrary write primitive.
* Privileged kernel/device-management memory corruption path: +1
  The parsing happens in the trusted i915 display BIOS/VBT path, using firmware-provided data in kernel driver initialization/configuration logic.
* Requires admin/root/firmware-level control in typical deployments: -2
  On normal bare-metal systems, modifying VBT/firmware or influencing BIOS tables usually requires administrative, firmware, or physical/platform-level control.
* Confidentiality impact plausible: +1
  If the invalid selector is later used as a table index, limited kernel-side OOB read of adjacent firmware/table data is plausible.
* Availability impact realistic: +1
  Invalid panel selection can plausibly break display initialization or cause driver malfunction, though no reliable panic is shown.

Paranoid-only interpretation additions:

* Local reduced-privilege trigger: +1
  In virtualized, firmware-emulation, device-passthrough, or platform-management environments, a reduced-privilege local actor or service might influence supplied display/VBT-like data without full host-root equivalence.
* Integrity impact plausible: +1
  Integrity is limited and indirect, based on possible incorrect panel configuration or invalid device state, not a demonstrated write primitive.

Offsetting constraints:

* No remote reachability.
* No strong memory corruption primitive is demonstrated.
* No UAF, double free, OOB write, type confusion, callback corruption, or controlled overwrite is shown.
* This remains an input-validation/range-check issue, so Important-class escalation is not strongly supported.

## 3. Reachability analysis

Typical trigger requires malformed or attacker-influenced i915 VBT / LFP Data Block contents, specifically an invalid `panel_type2` used for an LFP2 child device. On normal bare-metal systems, that usually means firmware/BIOS control, platform provisioning control, or administrative-level ability to modify firmware-supplied graphics metadata.

Namespaces and ordinary containers generally do not help, because this is not a normal unprivileged syscall, netlink, or device-node API path. A paranoid PR:L interpretation is defensible only for environments where a reduced-privilege local actor can influence virtual firmware tables, emulated platform data, or device configuration supplied to the i915 driver.

The path is not network reachable. The affected subsystem is common on Intel graphics systems, but the vulnerable condition depends on LFP2 panel metadata and malformed VBT contents.

Call-site confidence: medium. The patch shows the selector validation site and later selection logic, but not all downstream table users of the selected panel type.

## 4. Severity interpretation

This behaves like an actionable Moderate rather than a clear Important. The realistic impact is malformed firmware data causing incorrect panel selection, possible limited OOB read, or display/device initialization failure.

The theoretical risk is higher than a pure correctness issue because an unchecked firmware-derived selector enters trusted kernel display parsing logic. However, the patch does not support strong LPE, arbitrary write, attacker-controlled memory corruption, or remote exploitation. The conservative score remains borderline, while the paranoid score reaches Actionable Moderate due to firmware-mediated input plus weak OOB/indexing concerns.

## 5. One-sentence report phrase

An unchecked `panel_type2` value in i915 VBT parsing can allow malformed firmware-supplied display metadata to select an invalid LFP2 panel type, plausibly causing limited out-of-bounds table access or display initialization DoS, with typical exploitation requiring firmware or platform-data control.

## 6. Manual review recommendation

MANUAL CHECK RECOMMENDED

Reason: the patch is primarily a range-check fix, but it affects firmware-fed kernel display parsing and an unchecked table selector confirmed by Intel Product Security. It should not be auto-closed without checking downstream uses of the selected panel type for OOB read/write or persistent device-state impact.

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

Patch: drm/i915/bios: range check LFP Data Block panel_type2
Commit: e7b5694645b03e80830dc141b59fc65aac693c70
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=e7b5694645b03e80830dc141b59fc65aac693c70

Commit description:

While the panel_type from LFP Data Block is range checked, panel_type2
is not. Add a few helpers for range checking, and use them to not only
check panel_type2, but also improve clarity and correctness in the panel
type selection.

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

v2:
- Fix commit message typo (Michał)
- Add is_panel_type_pnp() (Ville)

Reported-by: Martin Hodo <martin.hodo@intel.com>
Fixes: 6434cf6 ("drm/i915/bios: calculate panel type as per child device index in VBT")
Cc: stable@vger.kernel.org # v6.0+
Cc: Animesh Manna <animesh.manna@intel.com>
Cc: Ville Syrjälä <ville.syrjala@intel.com>
Reviewed-by: Michał Grzelak <michal.grzelak@intel.com> # v1
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patch.msgid.link/20260626140155.1389655-1-jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
(cherry picked from commit c9ebe5d )
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/display/intel_bios.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=e7b5694645b03e80830dc141b59fc65aac693c70

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

The original Linux kernel CVE announcement for CVE-2026-68247 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68247

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:H/UI:N/S:U/C:L/I:N/A:L
  The Best / paranoid CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:H
  The Best / paranoid CVSS score: 5.8

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: 5

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 7.0

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).