CVE-2026-56129 Overview
CVE-2026-56129 affects the Generic IO & Memory Access driver for PCs provided by TOSHIBA CORPORATION and Dynabook Inc. The driver exposes an I/O Control (IOCTL) interface with insufficient access control, allowing a logged-in user without administrative privileges to read or write physical memory. This vulnerability is classified under [CWE-782] (Exposed IOCTL with Insufficient Access Control) and is exploitable locally. Successful exploitation enables privilege escalation, kernel tampering, and theft of sensitive data resident in physical memory.
Critical Impact
A non-administrative local user can access raw physical memory through the driver's IOCTL interface, enabling privilege escalation and disclosure of kernel-resident secrets.
Affected Products
- Generic IO & Memory Access driver for PCs (TOSHIBA CORPORATION)
- Generic IO & Memory Access driver for PCs (Dynabook Inc.)
- Sharp branded PCs distributing the affected driver (refer to vendor advisory for specific models)
Discovery Timeline
- 2026-06-25 - CVE-2026-56129 published to NVD
- 2026-06-25 - Last updated in NVD database
Technical Details for CVE-2026-56129
Vulnerability Analysis
The Generic IO & Memory Access driver operates as a kernel-mode component that provides controlled access to hardware resources including physical memory, port I/O, and memory-mapped I/O regions. The driver registers an IOCTL handler that should be restricted to privileged callers but instead accepts requests from any authenticated session. A local user can open a handle to the driver's device object and submit IOCTL requests that map or directly read and write arbitrary physical memory ranges.
Access to physical memory effectively bypasses the operating system's memory protection model. An attacker can locate kernel structures, modify process tokens, disable security callbacks, or extract credentials and cryptographic keys held in non-paged pool.
Root Cause
The root cause is missing or inadequate access control on the driver's IOCTL dispatch routine, corresponding to [CWE-782]. The driver does not validate the caller's security context against the sensitivity of the operation. Functions intended for administrative diagnostic use are reachable from a Medium integrity, non-elevated user session. The device object's discretionary access control list (DACL) and IOCTL access checks fail to restrict privileged operations to SYSTEM or administrators.
Attack Vector
Exploitation requires local authenticated access with no user interaction and low attack complexity. An attacker opens the driver's device using CreateFile against the published symbolic link, then issues DeviceIoControl calls with the specific control codes that map or read physical memory pages. By reading the kernel image and traversing EPROCESS structures, the attacker locates their process token and replaces it with the SYSTEM token, achieving full privilege escalation. See the JVN Security Vulnerability Report for additional technical context.
Detection Methods for CVE-2026-56129
Indicators of Compromise
- Unexpected user-mode processes opening handles to the Generic IO & Memory Access driver's device object
- Non-administrative processes issuing DeviceIoControl calls to the affected driver
- Sudden token replacement or integrity level elevation on processes that did not invoke a legitimate UAC prompt
- Loading of the vulnerable driver on systems where it is not required for operation
Detection Strategies
- Inventory endpoints for presence of the Toshiba/Dynabook Generic IO & Memory Access driver and flag installations outside expected hardware platforms
- Monitor kernel object access events for handles opened to the driver by non-administrative SIDs
- Hunt for sequences combining driver handle acquisition followed by privilege changes on the calling process
Monitoring Recommendations
- Enable Windows kernel auditing for driver load events (Event ID 6 in the System log) and correlate with process creation
- Forward Sysmon Event ID 1 (process create) and Event ID 11 (file create) to a central data lake for retrospective hunting on driver filenames
- Alert on any local interactive user account opening device objects associated with physical memory drivers
How to Mitigate CVE-2026-56129
Immediate Actions Required
- Identify all endpoints with the Generic IO & Memory Access driver installed and validate business need
- Uninstall or disable the driver on systems where it is not required for hardware functionality
- Restrict local logon rights on affected systems to reduce the population of users able to invoke the IOCTL
Patch Information
Refer to the vendor advisories for the current patch status and fixed driver versions. See the Sharp Corporate Security Advisory, the Sharp Global Security Advisory, and the JVN Security Vulnerability Report. Apply the vendor-supplied driver update once available and verify the driver version after installation.
Workarounds
- Remove the driver from endpoints where it is not actively in use
- Apply application control or Windows Defender Application Control (WDAC) policies to block loading of the vulnerable driver version
- Use Microsoft's vulnerable driver blocklist mechanisms to prevent the driver from being loaded by attackers who side-load it
# Query for the driver presence on Windows endpoints
sc.exe query type= driver | findstr /I "GenericIO"
# Remove the driver service if not required
sc.exe delete <DriverServiceName>
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
