[CVE-2026-68254][LOW] drm/i915/vrr: require valid min/max vfreq for VRR [ Upstream

[CVE-2026-68254][LOW] drm/i915/vrr: require valid min/max vfreq for VRR [ Upstream

[AL-KERNEL]

CVE: CVE-2026-68254
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: drm/i915/vrr: require valid min/max vfreq for VRR [ Upstream
Commit: 6598ac1721c3a5543efdbcab579a8561268d7ce1
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=6598ac1721c3a5543efdbcab579a8561268d7ce1
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68254
Analysis date: Mon, 10 Aug 2026 12:00:16 -0400
ActionableScore: 2
ActionableScore lower bound: 1
Actionable bucket: Ordinary Moderate / Low-like
Manual review required: NO

Summary:
Malformed EDID VRR frequency limits in i915 can allow a malicious display path to trigger a divide by zero in VRR computation, causing a kernel crash or display subsystem DoS without evidence of memory corruption or privilege escalation.

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

The original Linux kernel CVE announcement for CVE-2026-68254 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68254

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-2026-68254	LOW	CHECK WITH IMPACT FROM ORIG NN LOW	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H';CWE-369;*CWE-20;CWE-754;Other CVSS 'AV:P/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H';BEST CVSS score: '4.6';DESCR 'A divide by zero can occur in the i915 VRR path when EDID provided monitor_range min_vfreq or max_vfreq values are invalid, especially when min_vfreq is zero. A malicious or malformed display EDID from a monitor, dock, adapter, or KVM can make the driver accept an invalid VRR range and later reach the VRR calculation path that may crash the kernel. For the CVSS the PR:N is used in the paranoid physical device scenario because the attacker does not need an authenticated user account on the victim, only control of the EDID source connected to the display path. The issue is not network reachable. Impact is denial of service only via kernel crash or display subsystem failure.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 2)	YES	SIMPLEFIX HARDWARE 	YES	NO	checked

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

ActionableScore=2
ActionableScoreLower=1

## 1. ActionableScore

* Conservative score: 1
* Paranoid score: 2
* Final recommended bucket: **Ordinary Moderate / Low-like**::

## 2. Signal breakdown

Conservative signals:

* Firmware-mediated external influence: +1. The attacker influence is through malformed EDID data supplied by a display, dock, adapter, or KVM device, not through a normal network or local userspace API.
* Reliable kernel crash / strong DoS: +1. The commit states that a zero min_vfreq could lead to division by zero in intel_vrr_compute_vmax().
* Physical-only or rare hardware-only condition: -2. Practical triggering requires control over the connected display path or EDID source.

Paranoid additional signal:

* Availability impact realistic: +1. If a malicious EDID source is already connected or repeatedly presented during hotplug, resume, or modeset paths, the crash could be repeatedly triggered and affect host availability.

No memory corruption, UAF, OOB write, privilege escalation, confidentiality impact, or integrity impact is supported by the patch.

## 3. Reachability analysis

The bug is reachable through the i915 display VRR capability path when EDID monitor range values are invalid, especially when min_vfreq is zero. A realistic attacker would need physical or device-path influence, such as a malicious monitor, dock, adapter, KVM switch, or another EDID-providing component. A privileged local user may also be able to influence EDID through override or display configuration mechanisms, but that is not the main risk model.

This is not network reachable. Namespaces and containers do not materially lower the privilege requirement because the affected input is display hardware or privileged display configuration, not a namespaced userspace API. i915 is broadly deployed on Intel graphics systems, but VRR plus malformed EDID is a narrower trigger condition.

Call-site confidence: medium. The patch and commit identify the downstream divide-by-zero sink, but the full intel_vrr_compute_vmax call chain is not included in the provided diff.

## 4. Severity interpretation

This behaves like an ordinary Moderate or Low-like kernel DoS issue, not an Important-class vulnerability. The concrete primitive is division by zero, which supports availability impact only. There is no evidence of attacker-controlled memory corruption, stale object reuse, overwrite, information disclosure, or privilege escalation.

The paranoid score stays low because the worst supported outcome is a crash from malformed EDID. The physical or device-mediated trigger substantially limits practical exploitation compared with local unprivileged or network-reachable kernel bugs.

## 5. One-sentence report phrase

Malformed EDID VRR frequency limits in i915 can allow a malicious display path to trigger a divide by zero in VRR computation, causing a kernel crash or display subsystem DoS without evidence of memory corruption or privilege escalation.

## 6. Manual review recommendation

NO MANUAL CHECK NEEDED

This can be handled as a low-priority DoS-only issue because the patch shows input validation for EDID min and max frequency values and the only described failure mode is division by zero. There is no supported memory corruption or security-boundary bypass primitive.

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

Patch: drm/i915/vrr: require valid min/max vfreq for VRR [ Upstream
Commit: 6598ac1721c3a5543efdbcab579a8561268d7ce1
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=6598ac1721c3a5543efdbcab579a8561268d7ce1

Changed files:
  drivers/gpu/drm/i915/display/intel_vrr.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=6598ac1721c3a5543efdbcab579a8561268d7ce1

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

The original Linux kernel CVE announcement for CVE-2026-68254 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68254

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:P/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS vector: AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS score: 4.6

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: 1
  Paranoid ActionableScore: 2

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).