Which versions of Tosrfec Sys are affected by EUVD-2026-21848?

CVE-2026-35553 is a stack-based buffer overflow in Dynabook Bluetooth ACPI drivers that allows local administrators to execute arbitrary code and achieve complete system compromise.

How to fix or mitigate EUVD-2026-21848?

Within 24 hours: Identify all Dynabook systems with tosrfec.sys or drfec.sys drivers installed using hardware inventory tools and isolate any critical systems from general user access. Within 7 days: Contact Dynabook for patch availability timeline and implement compensating controls (see below). Within 30 days: Establish a monitoring plan for vendor advisory updates and evaluate replacement or hardware refresh strategies for affected Dynabook systems if patches remain unavailable.

Tosrfec Sys EUVD-2026-21848

Q: What is the CVSS score of EUVD-2026-21848?

EUVD-2026-21848 has a CVSS 4.0 base score of 8.4 (High). CVSS vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/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. EPSS exploitation probability: 0.0%.

| CVE-2026-35553 HIGH

Stack-based Buffer Overflow (CWE-121)

2026-04-13 jpcert

GHSA-gp9q-xqfw-39jw

Stack Overflow Buffer Overflow RCE Tosrfec Sys Drfec Sys

8.4

CVSS 4.0 · NVD

Severity by source

NVD PRIMARY

8.4 HIGH

CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/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

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/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

Attack Vector

Local

Attack Complexity

Low

Privileges Required

High

User Interaction

None

Scope

Lifecycle Timeline

Analysis Generated

Apr 13, 2026 - 05:26 vuln.today

Severity Changed

Apr 13, 2026 - 05:22 NVD

MEDIUM HIGH

CVSS changed

Apr 13, 2026 - 05:22 NVD

6.7 (MEDIUM) 8.4 (HIGH)

EUVD ID Assigned

Apr 13, 2026 - 05:15 euvd

EUVD-2026-21848

Analysis Generated

Apr 13, 2026 - 05:15 vuln.today

CVE Published

Apr 13, 2026 - 04:03 nvd

HIGH 8.4

DescriptionCVE.org

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.

AnalysisAI

Stack-based buffer overflow in Dynabook Bluetooth ACPI drivers (tosrfec.sys, drfec.sys) allows local administrators to execute arbitrary code by manipulating specific registry values. This CVSS 8.4 vulnerability requires high privileges (administrative access) but enables complete system compromise with low attack complexity. No public exploit identified at time of analysis, though the attack surface is limited to users who already possess elevated credentials.

Technical ContextAI

This vulnerability affects Dynabook Inc.'s Bluetooth ACPI drivers, specifically tosrfec.sys and drfec.sys kernel-mode components. The flaw is a CWE-121 stack-based buffer overflow, a class of memory corruption where user-controllable data exceeds allocated stack buffer boundaries. The attack vector involves modifying Windows registry values that are processed by these drivers without proper bounds checking. When the driver reads the malicious registry data, it overflows a stack buffer, allowing attackers to overwrite return addresses or other critical stack data structures. As kernel-mode drivers operate at Ring 0 with full system privileges, successful exploitation grants attackers complete control over the operating system. ACPI (Advanced Configuration and Power Interface) drivers interact with hardware power management, making them privileged components with deep system access. The registry-based attack surface is characteristic of Windows driver vulnerabilities where configuration parameters lack input validation.

RemediationAI

Apply vendor-provided security updates from Dynabook Inc. as detailed in Sharp Corporation's security advisories at https://global.sharp/corporate/info/product-security/advisory-list/2026-001/ (English) and https://corporate.jp.sharp/info/product-security/advisory-list/2026-001/ (Japanese). Consult JPCERT coordination notice at https://jvn.jp/en/vu/JVNVU96334293/ for comprehensive technical guidance and patch availability confirmation. Organizations should prioritize patching on systems where administrative access controls are weakest or where defense-in-depth protections against privilege escalation are critical. As an interim mitigation where patching is delayed, implement strict registry access controls using Windows ACLs to prevent unauthorized modification of registry keys processed by tosrfec.sys and drfec.sys drivers, though this workaround requires identifying the specific registry locations involved and may impact legitimate driver functionality. Monitor administrative account usage and registry modification events for suspicious activity targeting Bluetooth ACPI driver configuration paths.