CVE-2026-69910 in Windows
Summary
by MITRE • 09/09/2026
Stack-based buffer overflow in Windows Hyper-V allows an unauthorized attacker to execute code over a network.
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Analysis
by VulDB Data Team • 09/09/2026
The vulnerability described constitutes a critical security flaw within the Microsoft Windows Hypervisor, specifically affecting the virtualization infrastructure known as Hyper-V. This issue is classified as a stack-based buffer overflow, which represents one of the most prevalent and dangerous classes of memory corruption vulnerabilities in software engineering. In this specific context, the defect resides within components responsible for handling network traffic or hypervisor-to-guest communication protocols. When an attacker interacts with these interfaces over a network connection, they can supply input data that exceeds the allocated buffer size on the call stack. Because standard security controls such as stack cookies may be bypassed through sophisticated exploitation techniques, this overflow allows the attacker to overwrite adjacent memory locations, including return addresses or function pointers stored on the stack.
The technical mechanism behind this vulnerability relies on the improper validation of input data length before it is copied into a fixed-size buffer within the hypervisor's execution environment. Hypervisors operate at ring zero, granting them privileged access to hardware resources and all virtual machines running on the host system. Consequently, when an attacker successfully triggers the overflow by sending specially crafted network packets or RPC requests, they gain the ability to inject arbitrary machine code into the kernel-mode process space of the hypervisor. This results in remote code execution with SYSTEM-level privileges, effectively compromising the integrity of the entire physical host and all virtualized workloads residing upon it. The attack vector is particularly severe because it can be exploited remotely without requiring any user interaction or prior authentication on the target system, provided that network access to the vulnerable service endpoint exists.
From an operational impact perspective, successful exploitation leads to a complete compromise of the underlying infrastructure. An attacker who achieves code execution within the hypervisor context can bypass all guest operating system security boundaries. This allows for lateral movement across virtual machines, extraction of sensitive data from isolated environments, and persistence mechanisms that survive reboots or VM resets. Furthermore, because the vulnerability exists in the core virtualization layer, it undermines the fundamental trust model of cloud computing and enterprise server consolidation. Security researchers often map this type of flaw to Common Weakness Enumeration identifiers such as CWE-121 for stack-based buffer overflow and potentially CWE-787 if out-of-bounds writes are involved. In terms of tactical behavior, exploitation aligns with MITRE ATT&CK techniques related to privilege escalation from a lower integrity level to higher privileged contexts, specifically leveraging kernel or hypervisor vulnerabilities to establish persistent control over the host infrastructure.
Mitigation strategies must prioritize immediate patching and network segmentation due to the high severity of this vulnerability. Organizations should apply the latest cumulative security updates provided by Microsoft for their Windows Server versions hosting Hyper-V roles. Until patches are applied, it is advisable to restrict access to hypervisor management interfaces and RPC endpoints using strict firewall rules that limit connectivity only to trusted administrative subnets. Additionally, enabling hardware-enforced stack protection features such as Control Flow Guard (CFG) on supported operating systems can mitigate the likelihood of successful code execution by randomizing control flow targets and preventing direct jumps to injected shellcode. Regular vulnerability scanning focused on hypervisor components and continuous monitoring for anomalous network traffic patterns directed at virtualization services are essential defensive measures to detect potential exploitation attempts in real-time.