Description

Stack-based buffer overflow in Windows Hyper-V allows an unauthorized attacker to execute code over a network.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "9.8",
  "pubDate": "2026-09-08T18:20:02.250Z",
  "pubdate": "2026-09-08T18:20:02.250Z",
  "executiveSummary": "This vulnerability is identified as a stack-based buffer overflow within the Windows Hyper-V virtualization architecture. The flaw permits an unauthorized, remote attacker to execute arbitrary code within the context of the host system. By sending a specially crafted sequence of network packets to the Hyper-V host, an adversary can trigger memory corruption, potentially leading to a complete compromise of the virtualization layer. This vulnerability poses a critical risk to data center infrastructure, as it facilitates unauthorized code execution without requiring prior authentication. Successful exploitation allows for lateral movement, privilege escalation, and full control over guest and host environments. Given the network-accessible nature of this vector, systems are highly exposed, necessitating immediate patching and strict network segmentation to prevent potential weaponization by malicious actors.",
  "technicalDetails": "The vulnerability resides in the way Windows Hyper-V processes incoming network packets within its hypervisor-managed virtual switch or management stack. A stack-based buffer overflow occurs when the internal handling logic fails to properly sanitize the length of inbound data before copying it into a fixed-size stack buffer. Because the buffer is allocated on the stack rather than the heap, an attacker can precisely control the data being written, allowing for the overwriting of critical execution state markers, such as the function return address.\nThe exploitation process generally follows a multi-stage flow. Initially, the attacker transmits a series of malicious network frames designed to traverse the virtual switch and reach the vulnerable component. Upon receipt, the Hyper-V component attempts to process these inputs using an insecure memory operation, such as memcpy or a similar unchecked buffer write operation. By providing a payload exceeding the allocated buffer capacity, the attacker forces a stack overflow.\nOnce the buffer boundary is surpassed, the attacker can overwrite the saved return pointer on the stack. In a sophisticated execution flow, this facilitates a Control-Flow Hijack, where the instruction pointer is redirected to attacker-controlled memory. If the environment lacks modern exploit mitigations like Supervisor Mode Execution Prevention (SMEP) or robust Address Space Layout Randomization (ASLR), the attacker may successfully execute arbitrary shellcode or perform a Return-Oriented Programming (ROP) chain to gain higher-level privileges on the host system.\nBecause the vulnerable code operates at high privilege levels within the virtualization kernel, the impact is severe. Successful exploitation grants the attacker the ability to bypass virtual machine boundaries, potentially enabling escape from the guest context into the host kernel environment. This level of access grants the adversary total control over the physical host and all other virtual machines co-resident on that hardware. The exploit does not require the attacker to possess pre-existing credentials, making it highly attractive for remote, unauthenticated attacks against exposed virtualization endpoints."
}