CVE-2026-69548 in Windows
Summary
by MITRE • 09/09/2026
Heap-based buffer overflow in Windows RNDIS allows an unauthorized attacker to disclose information with a physical attack.
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Analysis
by VulDB Data Team • 09/09/2026
The vulnerability identified as a heap-based buffer overflow within the Remote Network Driver Interface Specification (RNDIS) implementation on Microsoft Windows represents a significant security risk, particularly for devices that are frequently connected to untrusted or compromised hosts via USB connections. RNDIS is a protocol used by mobile phones and other network-capable devices to emulate an Ethernet interface over USB, allowing them to share their internet connection with a computer. When a device utilizing this protocol connects to a Windows-based system, the operating system loads drivers that parse incoming data packets from the connected peripheral. The flaw resides in how these drivers handle specific malformed or maliciously crafted RNDIS messages during the initialization and configuration phases of the network interface.
At its core, this is a CWE-122 heap-based buffer overflow vulnerability. This type of memory corruption occurs when a program writes data beyond the boundaries of a allocated region on the heap. In the context of Windows RNDIS drivers, an attacker who has physical access to the target machine can exploit this flaw by connecting a malicious USB device that sends specially crafted network packets. These packets are designed to trigger a write operation that exceeds the size of the pre-allocated buffer in memory. Because the overflow occurs on the heap rather than the stack, it allows for more complex exploitation techniques and potentially greater control over the affected process's memory layout compared to traditional stack-based overflows.
The primary impact of this vulnerability is information disclosure, although depending on the specific version of Windows and the exact nature of the overwritten data, it could theoretically lead to code execution or denial of service conditions. The immediate consequence described in reports is that an unauthorized attacker can read sensitive memory contents from the host system. This disclosed information may include cryptographic keys, session tokens, passwords stored in memory, or other confidential data processed by network-related services running on the machine. Since RNDIS drivers operate with high privileges to manage network interfaces, the compromised process often has access to a wide array of system resources, amplifying the value of any leaked data.
From an operational perspective, this vulnerability highlights the risks associated with physical attack vectors and the trust model inherent in USB connectivity protocols. An attacker does not need remote access or user interaction beyond physically plugging in their device. This makes it particularly dangerous for mobile workforces, public computing environments, or systems handling sensitive corporate data where perimeter defenses like firewalls are ineffective against direct hardware connections. The ability to exploit this flaw via physical proximity means that traditional network security controls offer no protection, requiring a shift toward endpoint hardening and strict USB port management policies.
To mitigate the risks associated with this heap-based buffer overflow in Windows RNDIS, organizations should implement comprehensive device control strategies. This includes disabling unnecessary USB ports or restricting them to authorized devices only through Group Policy settings or third-party endpoint security solutions. Keeping all operating systems and drivers up to date is critical, as Microsoft has released patches addressing the underlying memory handling flaws in subsequent updates. Additionally, deploying Endpoint Detection and Response (EDR) tools can help monitor for anomalous behavior indicative of exploitation attempts, such as unusual memory access patterns by network driver processes. Users should also be educated on the risks of connecting unknown USB devices to corporate or personal computers, treating them with the same level of suspicion as untrusted external storage media.
This vulnerability aligns with ATT&CK technique T1059 Command and Scripting Interpreter if exploitation leads to further lateral movement, but primarily it falls under initial access vectors related to physical interaction. It also relates to CWE-284 Improper Access Control regarding the lack of sufficient validation on data received from external sources before processing. Addressing this issue requires a combination of technical patches, configuration hardening, and user awareness training to reduce the attack surface presented by USB-connected peripherals that utilize RNDIS for network connectivity.