EUVD-2026-39190
GHSA-62xh-mjg9-8qhv
Severity by source
CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Physical memory access enables both read and write; C:H added to correct apparent understatement of vendor C:N, all other metrics align with the provided vector.
Primary rating from Vendor (jpcert).
CVSS VectorVendor: jpcert
Lifecycle Timeline
2DescriptionCVE.org
Generic IO & Memory Access driver for PCs provided by TOSHIBA CORPORATION and Dynabook Inc. exposes its IOCTL with insufficient access control. A logged-in user with no administrative privilege may access physical memory.
AnalysisAI
Physical memory exposure in the Generic IO & Memory Access Driver for Toshiba and Dynabook PCs allows any locally logged-in user - without administrative privileges - to access physical memory by invoking an insufficiently access-controlled IOCTL interface. Physical memory access of this kind typically enables both reading sensitive in-memory data (credentials, encryption keys, kernel structures) and writing to arbitrary memory addresses, making the effective impact broader than the vendor CVSS C:N rating suggests. No public exploit or CISA KEV listing has been identified at time of analysis; this was disclosed via JPCERT/JVN and a Sharp/Dynabook security advisory.
Technical ContextAI
The affected component is the Generic IO & Memory Access driver, a kernel-mode Windows driver distributed by Toshiba Corporation and Dynabook Inc. (CPE: cpe:2.3:a:dynabook_inc.:generic_io_&_memory_access_driver and cpe:2.3:a:toshiba_corporation:generic_io_&_memory_access_driver). Kernel drivers expose device I/O control (IOCTL) interfaces to userland processes. CWE-782 (Exposed IOCTL with Insufficient Access Control) describes a class of flaw where the driver's IOCTL dispatch routine fails to enforce security descriptor restrictions, meaning low-privileged processes can issue privileged IOCTL codes. Drivers that expose physical memory mapping (e.g., MmMapIoSpace or ZwMapViewOfSection over physical addresses) are particularly dangerous when their access is unrestricted, as physical memory access bypasses all OS-level privilege boundaries.
RemediationAI
Consult the Sharp/Dynabook security advisory at https://global.sharp/corporate/info/product-security/advisory-list/2026-003/ for the exact patched driver version; the input data does not specify a fixed version number, so a precise upgrade target cannot be confirmed independently. The JVN advisory at https://jvn.jp/en/vu/JVNVU91051826/ may provide additional version guidance. As a compensating control pending a patch, administrators can restrict access to the driver device object via a custom security descriptor policy using tools such as sc.exe or Group Policy to deny non-administrator processes from opening the driver handle - this directly addresses the CWE-782 root cause without requiring driver replacement, but may break any legitimate vendor software that relies on the driver for non-privileged access. Alternatively, if the driver is not required for normal operation, uninstalling or disabling it via Device Manager eliminates the attack surface entirely with no functional side effects on most systems.
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External POC / Exploit Code
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