[CVE-2026-89822][LOW] drm/i915: Guard against NULL driver_data in i915_pci_probe()

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

CVE: CVE-2026-89822
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: drm/i915: Guard against NULL driver_data in i915_pci_probe()
Commit: 2239e6b49d33bb38817d69b4f0bf7d5cbde2ec68
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=2239e6b49d33bb38817d69b4f0bf7d5cbde2ec68
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-89822
Analysis date: Wed, 16 Sep 2026 14:20:37 -0400
ActionableScore: 0
ActionableScore lower bound: unknown
Actionable bucket: Ordinary Moderate
Manual review required: NO

Summary:
No one-sentence report phrase was found.

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

The original Linux kernel CVE announcement for CVE-2026-89822 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-89822

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.

======================================================================
AL-KERNEL CLASSIFICATION RESULT
======================================================================

CVE-2026-89822	LOW	https://www.kernelcve.org/list/?q=CVE-2026-89822 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-754;*CWE-20;Other CVSS 'AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '5.5';DESCR 'i915_pci_probe can dereference a NULL intel_device_info pointer when a PCI device is force bound through sysfs driver_override and pci_match_device returns the dummy pci_device_id_any entry with no driver_data. This allows a local actor who can control PCI driver binding to trigger a kernel NULL pointer dereference during probe. For the CVSS the PR:L is used only for the paranoid score because some environments may delegate reduced device management capabilities to a service account or container root, while the normal host configuration requires administrator privileges. The issue is not network reachable and is triggered through local sysfs control plane operations. Impact is denial of service via kernel oops or panic. There is no supported path to confidentiality impact, integrity impact, or privilege escalation because the patch shows a NULL dereference guard rather than UAF, OOB access, or writable memory corruption.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 0)	YES	DANGER NULLPTR SIMPLEFIX HARDWARE SYZBOT  DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3	NO	NO	checked

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

ActionableScore=0
PrimitiveClass=CLASS_C
RealUAF=NO
HostAdminRequired=YES
NamespaceScopedPrivilege=NO
ImportantCandidate=NO
ManualReview=NO
AutoDowngradeAllowed=YES

1. ActionableScore

* Raw conservative score: -1
* Conservative score: 0
* Raw paranoid score: -1
* Paranoid score: 0
* Applied floor/cap: raw score floored from -1 to 0 because ActionableScore is not negative.
* Final recommended bucket: **Ordinary Moderate**::

2. Signal breakdown

Positive signals:

* +1 Reliable kernel crash / strong DoS: the patch and commit establish a NULL pointer dereference in `i915_pci_probe()` when `ent->driver_data` is NULL, which can cause kernel oops or panic depending on system policy.

Negative signals:

* -2 Host-admin-equivalent privilege required: the trigger requires force-binding a PCI device through sysfs `driver_override` and driver bind/probe control, which is host-level device management and is normally restricted to root or equivalent host administration.

Non-awarded material signals:

* Real UAF not awarded: the bug is a NULL pointer dereference, not stale post-lifetime object use.
* Concrete repeated release/refcount not awarded: no put/free/release/refcount mutation occurs on a dangling reference.
* Structured stale-object leverage not awarded: there is no stale structured object reuse, only a NULL check before dereference.
* Controlled reclaim not demonstrated.
* Arbitrary or directed kernel write not demonstrated.
* Confidentiality and integrity impact not awarded: no read-back, disclosure, unauthorized modification, or memory corruption primitive is established.
* Remote reachability not awarded: the trigger is a local sysfs PCI driver-binding control-plane operation.
* Extra availability point not awarded: the same oops/panic is already counted as reliable DoS.
* Weak LPE or strong LPE not awarded: no path beyond crash is supported by the patch or supplied context.

3. Reachability analysis

The triggering actor must be able to force-bind a PCI device to the i915 driver through sysfs `driver_override`, causing `pci_match_device()` to return the dummy `pci_device_id_any` entry whose `driver_data` is NULL. This is a host PCI driver-management operation, not an ordinary DRM/KMS display operation.

The supplied evidence does not establish reachability by an ordinary logged-in desktop user, DRM master, compositor, or seat-local display service. The complete vulnerable operation is PCI device binding/probing, which is host-global and not namespace-scoped. No network trigger is present. No special rare hardware penalty is applied because i915/GPU hardware is common, but the vulnerable operation itself is privileged host device management. No race or difficult timing is required.

4. Primitive and severity interpretation

The exact primitive is an invalid NULL pointer dereference of `intel_info->require_force_probe` after `ent->driver_data` is cast to `struct intel_device_info *` without checking for NULL. This is not active structured UAF, not fixed stale storage, and not a repeated lifetime/refcount mutation.

PrimitiveClass is CLASS_C because the established behavior is crash/DoS from invalid state, without an independently useful corruption, ownership, authorization, or disclosure primitive. The demonstrated consequence is kernel oops or panic. Theoretical privilege escalation is not supported because the patch only adds a NULL guard and does not indicate UAF, OOB access, type confusion, writable memory corruption, callback control, or refcount/lifetime corruption.

ImportantCandidate is NO because no Important-grade primitive or unresolved Class B lifetime/corruption leverage exists. AutoDowngradeAllowed is YES because this is a host-admin-gated NULL dereference DoS with no meaningful unresolved exploitation primitive beyond crash.

5. One-sentence report phrase

A host administrator who can force bind PCI devices through sysfs driver_override can trigger a NULL pointer dereference in i915_pci_probe, causing a local kernel DoS without evidence of memory corruption, information disclosure, or privilege escalation.

6. Manual review recommendation

NO MANUAL CHECK NEEDED

Reason: this is a straightforward host-admin-gated NULL pointer dereference with crash-only impact and no established UAF, repeated lifetime mutation, authorization bypass, or controlled corruption primitive.

7. Call-site confidence

Call-site confidence: high

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

Patch: drm/i915: Guard against NULL driver_data in i915_pci_probe()
Commit: 2239e6b49d33bb38817d69b4f0bf7d5cbde2ec68
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=2239e6b49d33bb38817d69b4f0bf7d5cbde2ec68

Commit description:

pci_match_device() can return the dummy pci_device_id_any entry
when a device is force-bound via sysfs driver_override, in which
case ->driver_data is unset (NULL). i915_pci_probe() casts it to
struct intel_device_info * unconditionally and dereferences
intel_info->require_force_probe, causing a NULL-ptr-deref.

Reported-by: syzbot+db96c5ff032f4292a8dc@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=db96c5ff032f4292a8dc
Tested-by: syzbot+db96c5ff032f4292a8dc@syzkaller.appspotmail.com
Cc: stable@vger.kernel.org
Signed-off-by: Deepanshu Kartikey <kartikey406@gmail.com>
Link: https://patch.msgid.link/20260813064902.367504-1-kartikey406@gmail.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
(cherry picked from commit 2727922 )
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Changed files:
  drivers/gpu/drm/i915/i915_pci.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=2239e6b49d33bb38817d69b4f0bf7d5cbde2ec68

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

The original Linux kernel CVE announcement for CVE-2026-89822 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-89822

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:L/PR:H/UI:N/S:U/C:N/I:N/A:H
  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: 0

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).