CVE-2026-35553: Dynabook Bluetooth Driver Overflow Flaw

CVE-2026-35553 Overview

Bluetooth ACPI Drivers provided by Dynabook Inc. contain a stack-based buffer overflow vulnerability. An attacker may execute arbitrary code by modifying certain registry values. This vulnerability (CWE-121) allows local attackers with high privileges to manipulate Windows Registry entries associated with the Bluetooth ACPI driver, potentially leading to arbitrary code execution with elevated system privileges.

Critical Impact

Stack-based buffer overflow in Bluetooth ACPI drivers enables arbitrary code execution through registry manipulation, potentially compromising system integrity and confidentiality.

Affected Products

• Bluetooth ACPI Drivers by Dynabook Inc.
• Systems with Sharp/Dynabook Bluetooth ACPI driver components installed

Discovery Timeline

• 2026-04-13 - CVE CVE-2026-35553 published to NVD
• 2026-04-13 - Last updated in NVD database

Technical Details for CVE-2026-35553

Vulnerability Analysis

This vulnerability represents a classic stack-based buffer overflow (CWE-121) within the Bluetooth ACPI driver components distributed by Dynabook Inc. The flaw exists in how the driver processes registry values, where insufficient bounds checking allows data larger than the allocated stack buffer to overwrite adjacent memory regions, including critical control structures such as return addresses.

When a privileged user modifies specific registry values associated with the Bluetooth ACPI driver to contain oversized data, the driver fails to properly validate the input length before copying it to a fixed-size stack buffer. This memory corruption condition can be leveraged to redirect program execution flow and achieve arbitrary code execution within the kernel context.

Root Cause

The root cause stems from improper input validation when reading registry values into stack-allocated buffers. The driver does not enforce proper boundary checks on the data retrieved from registry keys, allowing an attacker to craft malicious registry entries that exceed the expected buffer size. When the driver reads these malformed values, the oversized data overwrites the stack frame, corrupting the saved return pointer and potentially other critical execution metadata.

Attack Vector

The attack requires local access with high privileges to modify Windows Registry values. An attacker must:

1. Identify the specific registry keys used by the Bluetooth ACPI driver
2. Craft malicious registry values containing overflow payload data
3. Trigger the driver to read the malicious registry values
4. The overflow corrupts the stack, enabling redirection of execution flow

The vulnerability requires local access with elevated privileges, which limits the attack surface but still poses significant risk in scenarios involving insider threats, privilege escalation chains, or compromised administrator accounts.

Detection Methods for CVE-2026-35553

Indicators of Compromise

• Unexpected modifications to Bluetooth ACPI driver-related registry keys
• Abnormal registry value sizes or unusual data patterns in driver configuration entries
• System crashes or blue screens associated with Bluetooth ACPI driver components
• Suspicious process execution originating from driver context

Detection Strategies

• Monitor Windows Registry for unauthorized modifications to Bluetooth/ACPI driver configuration keys
• Implement registry auditing policies to log changes to driver-related registry paths
• Deploy endpoint detection solutions capable of identifying stack buffer overflow exploitation attempts
• Utilize kernel-level monitoring to detect anomalous driver behavior or memory corruption indicators

Monitoring Recommendations

• Enable Windows Security Event logging for registry access and modification events (Event ID 4657, 4663)
• Configure SentinelOne to monitor for suspicious registry manipulation patterns targeting driver components
• Implement baseline monitoring for normal registry value sizes to detect anomalous oversized entries
• Deploy kernel integrity monitoring to detect unauthorized code execution within driver context

How to Mitigate CVE-2026-35553

Immediate Actions Required

• Review and audit registry permissions for Bluetooth ACPI driver-related keys
• Restrict registry modification privileges to only essential administrative accounts
• Apply updated drivers from Dynabook Inc. or Sharp as soon as patches become available
• Consider temporarily disabling affected Bluetooth functionality if not critical to operations

Patch Information

Updated driver software addressing this vulnerability is expected from Dynabook Inc. Organizations should monitor the following security advisories for patch availability:

• Sharp Security Advisory 2026-001
• Sharp Global Security Advisory 2026-001
• JVN Vulnerability Report JVNVU96334293

Workarounds

• Restrict administrative access to systems with vulnerable Bluetooth ACPI drivers
• Implement registry access controls to limit modification capabilities for driver-related keys
• Deploy application control policies to prevent unauthorized driver component loading
• Consider using endpoint protection with exploit prevention capabilities to mitigate buffer overflow attacks

# Audit registry permissions for Bluetooth driver keys
# Example: Review current permissions on driver registry path
reg query "HKLM\SYSTEM\CurrentControlSet\Services" /s | findstr /i "bluetooth"

# Restrict modification access (requires administrative privileges)
# Apply least-privilege model to driver configuration registry keys