[CVE-2026-64231][LOW] drm/msm/dsi: don't dump registers past the mapped region [ Upstream

[CVE-2026-64231][LOW] drm/msm/dsi: don't dump registers past the mapped region [ Upstream

[AL-KERNEL]

CVE: CVE-2026-64231
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: drm/msm/dsi: don't dump registers past the mapped region [ Upstream
Commit: 5e2c196c3430fb94225c4102b1028d0146544761
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=5e2c196c3430fb94225c4102b1028d0146544761
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-64231
Analysis date: Fri, 24 Jul 2026 13:04:31 -0400
ActionableScore: 1
ActionableScore lower bound: unknown
Actionable bucket: Ordinary Moderate / Low-like
Manual review required: NO

Summary:
The MSM DSI snapshot path may read past the mapped DSI IO region after applying io_offset without reducing ctrl_size, causing a local platform-specific kernel fault or DoS without evidence of privilege escalation.

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

The original Linux kernel CVE announcement for CVE-2026-64231 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-64231

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-2026-64231	LOW	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:N/I:N/A:H';CWE-125;CWE-119;CWE-754;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '4.7';DESCR 'The MSM DSI driver can access past the mapped DSI IO region during display snapshot register dumping because ctrl_base is adjusted by io_offset but ctrl_size was not reduced accordingly. This can make msm_dsi_host_snapshot pass an oversized MMIO range into the snapshot path and may cause an invalid IO read, external abort, or kernel crash. For the CVSS the PR:L is used for the paranoid score because a local process that can influence display error handling or snapshot capture may be enough in some deployments, although reliable triggering is platform and configuration dependent. The issue is not network reachable. Impact is denial of service via kernel crash or fault during snapshot capture, with no supported evidence of privilege escalation or memory corruption.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 1)  SKIP CVE-2026-64231 UNKNOWN SKIP No affected files built, so skip this CVE NO  - - unknown 	MAYBE	OOB DANGER SIMPLEFIX HARDWARE LINUS  DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3	-	-	checked

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

ActionableScore=1

## 1. ActionableScore

* Conservative score: 1
* Paranoid score: 1
* Final recommended bucket: **Ordinary Moderate / Low-like**

## 2. Signal breakdown

Triggered signals:

* Reliable kernel crash / strong DoS: +1
  The commit describes access past the mapped DSI IO region during register snapshot dumping. This can plausibly cause an invalid MMIO read, external abort, or kernel fault in the snapshot worker path.

Not triggered:

* Remote reachable / network-triggerable: +0
  The affected path is DRM MSM DSI register snapshot handling, not a network or packet-processing path.

* Local unprivileged trigger: +0
  A local process may indirectly exercise display paths, but the provided patch does not show a reliable unprivileged trigger for the snapshot capture path.

* Generic memory corruption: +0
  This is an out-of-range MMIO/register read past a mapped IO window, not an OOB write, UAF, double free, type confusion, or attacker-controlled kernel memory corruption primitive.

* Privilege escalation plausible: +0
  No reclaim, overwrite, stale callback, object confusion, refcount abuse, or controlled write primitive is indicated.

* Confidentiality impact plausible: +0
  The bug reads outside the intended mapped device register range, but there is no shown user-visible disclosure path or leak of kernel memory.

* Integrity impact plausible: +0
  The patch prevents over-reading during dumping. It does not describe writes past bounds or corruption of kernel or device state.

Negative or limiting factors:

* Platform / path specificity: effectively limiting, but not scored below zero
  The issue is specific to MSM DSI 6G platforms and the display snapshot path.

Call-site confidence: high
The stack trace and changed fields show the relevant path through `msm_dsi_host_snapshot()` and snapshot capture.

## 3. Reachability analysis

The bug is reachable only on affected Qualcomm MSM DSI platforms where `io_offset` adjusts the mapped controller base and the snapshot path dumps the register region. The realistic trigger appears to be local display error handling, debug, or snapshot capture rather than ordinary remote input.

Namespaces and containers do not meaningfully improve reachability unless a container is granted access to DRM/display control interfaces. The path is not network reachable and is not a common default server exposure.

## 4. Severity interpretation

This behaves like an ordinary Moderate or Low-like kernel DoS issue. The theoretical issue is an out-of-bounds MMIO read past a mapped device region, but the realistic evidence points to a crash or fault during register dump, not to exploitable memory corruption or privilege escalation.

It should not be treated as an Important candidate based on the provided patch.

## 5. One-sentence report phrase

The MSM DSI snapshot path may read past the mapped DSI IO region after applying io_offset without reducing ctrl_size, causing a local platform-specific kernel fault or DoS without evidence of privilege escalation.

## 6. Manual review recommendation

NO MANUAL CHECK NEEDED

This can be auto-closed for most triage workflows because it is platform-specific, not remotely reachable, and shows only availability impact without a concrete memory corruption or privilege-escalation primitive.

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

Patch: drm/msm/dsi: don't dump registers past the mapped region [ Upstream
Commit: 5e2c196c3430fb94225c4102b1028d0146544761
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=5e2c196c3430fb94225c4102b1028d0146544761

Changed files:
  drivers/gpu/drm/msm/dsi/dsi_host.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=5e2c196c3430fb94225c4102b1028d0146544761

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

The original Linux kernel CVE announcement for CVE-2026-64231 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-64231

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:N/I:N/A:H
  The Best / paranoid CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
  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: unknown
  Paranoid ActionableScore: 1

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).