CVE-2026-70116 in Windows
Summary
by MITRE • 10/14/2026
Stack-based buffer overflow in Windows Resilient File System (ReFS) allows an unauthorized attacker to bypass a security feature with a physical attack.
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Analysis
by VulDB Data Team • 10/15/2026
The vulnerability identified involves a stack-based buffer overflow within the Microsoft Windows Resilient File System, commonly known as ReFS. This architectural flaw resides deep within the file system driver layer of the operating system kernel, where memory management is critical for maintaining system stability and security boundaries. The specific nature of this defect allows an attacker to overwrite adjacent memory locations on the call stack by supplying input data that exceeds the allocated buffer size. Because this vulnerability can be triggered through a physical attack vector, it implies that the exploit does not require remote network access or local user authentication in the traditional sense. Instead, an adversary with direct physical access to the machine's hardware interfaces can interact directly with storage devices connected via protocols such as USB, Thunderbolt, or FireWire to trigger the overflow condition during file system operations.
From a technical perspective, stack-based buffer overflows are among the most dangerous classes of memory corruption vulnerabilities because they allow for arbitrary code execution by manipulating the return address stored on the stack. When an attacker successfully exploits this flaw within ReFS, they can redirect the flow of program execution to malicious shellcode injected into the overflowed buffer or adjacent memory regions. This capability effectively neutralizes security features that rely on kernel-level integrity checks, such as Secure Boot configurations or BitLocker encryption protections if accessed during specific initialization phases. The ability to bypass these security mechanisms means that an attacker could potentially gain unrestricted administrative privileges (SYSTEM level) without triggering standard detection systems designed for remote exploitation attempts.
The operational impact of this vulnerability is severe due to its physical attack vector, which aligns with the ATT&CK technique T1217 Browser Rendering or more accurately in this context, hardware-based attacks like those described under T1059 Command and Scripting Interpreter when combined with local privilege escalation techniques. The primary risk involves the complete compromise of data confidentiality and integrity on systems where physical security is not strictly enforced. For environments utilizing ReFS for its resilience features against bit rot and corruption, this vulnerability introduces a significant threat surface that undermines trust in the storage layer itself. Attackers can use this method to extract sensitive information from encrypted volumes by manipulating boot processes or memory states before full encryption keys are securely loaded into protected hardware modules like TPMs.
Mitigation strategies for this class of vulnerabilities typically involve both software updates and physical security enhancements. Microsoft has addressed similar issues in ReFS through cumulative security updates that patch the underlying buffer handling logic, ensuring proper bounds checking is implemented during file system operations initiated by external storage devices. Organizations should prioritize applying these patches to all systems utilizing ReFS volumes. Additionally, since the attack vector relies on physical access, implementing strict physical security controls is essential. This includes securing server rooms and workstations with locked enclosures, disabling unused USB ports via Group Policy or BIOS settings, and employing hardware-based authentication methods that require additional credentials before allowing external storage devices to mount and interact with the file system. Regular auditing of connected peripherals and monitoring for anomalous kernel-level activity can also help detect attempted exploitation in real-time.