Microsoft Windows 10 1607/Server 2016 NAT memory corruption

Summaryinfo

A vulnerability, which was classified as critical, has been found in Microsoft Windows 10 1607/Server 2016. Affected by this issue is some unknown functionality of the component NAT. This manipulation causes memory corruption. This vulnerability is registered as CVE-2020-16894. Remote exploitation of the attack is possible. No exploit is available. It is suggested to install a patch to address this issue.

Detailsinfo

A vulnerability has been found in Microsoft Windows 10 1607/Server 2016 (Operating System) and classified as critical. Affected by this vulnerability is an unknown functionality of the component NAT. The manipulation with an unknown input leads to a memory corruption vulnerability. The CWE definition for the vulnerability is CWE-119. The product performs operations on a memory buffer, but it can read from or write to a memory location that is outside of the intended boundary of the buffer. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

<p>A denial of service vulnerability exists when Windows Network Address Translation (NAT) on a host server fails to properly validate input from a privileged user on a guest operating system. An attacker who successfully exploited the vulnerability could cause the host server to crash.</p> <p>To exploit the vulnerability, an attacker who already has a privileged account on a guest operating system, running as a virtual machine, could run a specially crafted application that causes a host machine to crash.</p> <p>The update addresses the vulnerability by modifying how Windows NAT accesses the host.</p>

The weakness was published 10/13/2020 as confirmed security guidance (Website). The advisory is shared at portal.msrc.microsoft.com. This vulnerability is known as CVE-2020-16894. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 02/24/2026). The advisory points out:

A remote code execution vulnerability exists when Windows Network Address Translation (NAT) fails to properly handle UDP traffic. To exploit the vulnerability, an attacker could run a specially crafted application on a guest operating system. An attacker who successfully exploited the vulnerability could cause memory corruption on a host operating system. The security update addresses the vulnerability by correcting how Windows NAT handles objects in memory.

It is declared as proof-of-concept.

Applying a patch is able to eliminate this problem. A possible mitigation has been published immediately after the disclosure of the vulnerability.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Type

• Operating System

Vendor

• Microsoft

Name

• Windows

Version

• 10 1607
• Server 2016

License

• commercial

Website

• Vendor: https://www.microsoft.com/
• Product: https://www.microsoft.com/en-us/windows

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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