[CVE-2026-72452][MODERATE 7.0] drm/i915: clear CRTC color blob pointers after dropping refs [ Upstream

[CVE-2026-72452][MODERATE 7.0] drm/i915: clear CRTC color blob pointers after dropping refs [ Upstream

[AL-KERNEL]

CVE: CVE-2026-72452
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: YES
Patch: drm/i915: clear CRTC color blob pointers after dropping refs [ Upstream
Commit: 164afa1a3af8e8c91b4a6d5fd7b79a44ec70abf0
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=164afa1a3af8e8c91b4a6d5fd7b79a44ec70abf0
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72452
Analysis date: Sun, 16 Aug 2026 07:52:56 -0400
ActionableScore: 6
ActionableScore lower bound: 5
Actionable bucket: Actionable Moderate at minimum
Manual review required: YES

Summary:
A stale pointer lifetime bug in `drm/i915` can cause CRTC color blob references to be dropped twice during repeated atomic cleanup after an error path, creating a local DoS and possible UAF or double-free candidate requiring manual review.

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

The original Linux kernel CVE announcement for CVE-2026-72452 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72452

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: YES

A detailed explanation of the methodology and priority rules is included
at the end of this message.

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

CVE-2026-72452	MODERATE	CHECK WITH IMPACT FROM ORIG NN MODERATE	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:H/A:H';CWE-415;*CWE-416;*CWE-672;Other CVSS 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '7';DESCR 'A stale pointer bug in drm i915 can leave CRTC color blob pointers unchanged after their references are dropped. If intel_crtc_prepare_cleared_state fails after freeing the old CRTC hardware state, the same failed atomic state can later be cleaned again by the atomic core and the same blob references can be dropped twice. This is at least a local denial of service risk through a kernel crash or refcount failure. In the worst defensible interpretation, the double put may become a use after free or double free candidate on DRM property blob objects and may allow confidentiality or integrity impact. For the CVSS the PR:L is used because a local user or process with access to DRM KMS atomic modeset paths may be able to trigger the faulty cleanup, while full root privileges are not necessarily required on desktop or compositor environments. The issue is not network reachable and requires local interaction with the graphics stack rather than packet input.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Actionable Moderate at minimum (with actual score 7)  SKIP CVE-2026-72452 UNKNOWN SKIP The Fixes patch not applied yet, so unlikely that actual: 77fcf58df15edcf3f5b5421f24814fb72796def9 YES  NO NO unknown 	MAYBE	DANGER SIMPLEFIX ERRORPATH HARDWARE KPANIC  KPANIC INCREASED_TO_HIGH_BASED_ON_ACTIONABLESCOREHIGHEREQTHAN6 DECREASED_TO_MODERATE7_BASED_ON_FALSEPOSCHECKOFDH	-	-	checked

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ACTIONABLESCORE ANALYSIS
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## 1. ActionableScore

ActionableScore=6
ActionableScoreLower=5

* Conservative score: 5
* Paranoid score: 6
* Final recommended bucket: **Actionable Moderate at minimum**::

## 2. Signal breakdown

Conservative signals:

* Local unprivileged trigger: +1
  Local DRM/KMS atomic modeset paths may be reachable by a local graphical user or compositor process, not necessarily full root.

* Generic memory corruption, strong corruption primitive: +2
  The bug is a repeated `drm_property_blob_put()` on stale pointers. This is a double-put / double-free / UAF candidate.

* Real lifetime corruption: +1
  The patch fixes object lifetime state by nulling pointers after dropping references.

* Reliable kernel crash / strong DoS: +1
  Repeated cleanup of the same state can drop the same blob references again, plausibly causing refcount failure, UAF, or crash.

* Broad/default/common subsystem: +1
  `drm/i915` is broadly deployed on Intel desktop and laptop systems.

Negative signals:

* Hard or special error path required: -1
  The described path depends on failed cleared-state preparation, for example `-EDEADLK` while handling DP tunnel group state.

Paranoid additional signal:

* Weak LPE concern: +1
  A double-put on DRM property blob objects is a lifetime corruption pattern that may be exploitable in some allocator/reclaim conditions, but no controlled reclaim, write primitive, callback control, or type confusion is demonstrated.

Call-site confidence: high. The commit message describes the relevant cleanup sequence and repeated call path.

## 3. Reachability analysis

The bug is local, not network reachable. A realistic trigger requires access to the DRM/KMS atomic modeset path and a failure in the cleared-state preparation sequence. On typical desktop systems, this may be reachable by a local graphical session, compositor, display server, or process with DRM master style access. It should not be treated as requiring full host root in all deployments.

Namespaces and containers usually do not make this broadly reachable unless the DRM device is passed through or exposed to the container. The affected subsystem is common on Intel GPU systems, but the specific DP tunnel and `-EDEADLK` cleanup path makes reliable triggering more conditional than a simple ioctl crash.

## 4. Severity interpretation

This is more than an ordinary Moderate because it is an object lifetime bug with repeated reference dropping, not just a warning or pure logic error. The conservative interpretation is an actionable local DoS with real lifetime corruption.

The Important-class interpretation is plausible but not proven. The patch supports a double-put / UAF candidate, but does not show attacker-controlled reclaim, controlled overwrite, type confusion, or a demonstrated LPE path. Therefore the best practical bucket is Actionable Moderate at minimum, with manual review recommended for possible Important classification.

## 5. One-sentence report phrase

A stale pointer lifetime bug in `drm/i915` can cause CRTC color blob references to be dropped twice during repeated atomic cleanup after an error path, creating a local DoS and possible UAF or double-free candidate requiring manual review.

## 6. Manual review recommendation

MANUAL CHECK REQUIRED

Reason: the patch fixes a real lifetime corruption pattern involving repeated reference drops on stale pointers in a common DRM driver. Even though exploitation beyond DoS is not demonstrated, the double-put / UAF candidate is strong enough that it should not be auto-closed.

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

Patch: drm/i915: clear CRTC color blob pointers after dropping refs [ Upstream
Commit: 164afa1a3af8e8c91b4a6d5fd7b79a44ec70abf0
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=164afa1a3af8e8c91b4a6d5fd7b79a44ec70abf0

Changed files:
  drivers/gpu/drm/i915/display/intel_atomic.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=164afa1a3af8e8c91b4a6d5fd7b79a44ec70abf0

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

The original Linux kernel CVE announcement for CVE-2026-72452 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72452

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:N/I:N/A:H
  The Best / paranoid CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
  The Best / paranoid CVSS score: 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: 5
  Paranoid ActionableScore: 6

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: YES
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).