CVE-2026-65789: Windows DNS Server Remote Code Execution Vulnerability

Overview

Severity

High (CVSS 8.1)

CVSS Vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C

Category

Remote Code Execution

Exploit Status

Not Exploited

Exploitation Likelihood

Unlikely

Patch Tuesday

2026-Aug

Released

2026-08-11

Last Updated

2026-09-08

EPSS Score

0.71% (percentile: 51.5%)

Description

Use after free in Windows DNS allows an unauthorized attacker to execute code over a network.

FAQ

According to the CVSS metric, the attack complexity is high (AC:H). What does that mean for this vulnerability? Exploitation requires specific conditions, including particular network configurations and timing conditions, and has only been observed in limited scenarios. This means an attacker cannot reliably exploit the issue in all environments and may need favorable setup or circumstances for it to work. How could an attacker exploit this vulnerability? An unauthenticated attacker could exploit this vulnerability by sending a specially crafted packet to an affected service over the network. Successful exploitation could allow the attacker to execute code on the target system. No authentication or user interaction is required.

Affected Products (8)

Windows

• Windows Server 2019
• Windows Server 2019 (Server Core installation)
• Windows Server 2022
• Windows Server 2022 (Server Core installation)
• Windows Server 2025 (Server Core installation)
• Windows Server 2025
• Windows Server 2016
• Windows Server 2016 (Server Core installation)

Security Updates (6)

• 5120238
• 5120242
• 5120229
• 5120233
• 5120228
• 5120418

Acknowledgments

<a href="https://x.com/dark_puzzle">Souhail Hammou</a>

Revision History

• 2026-08-11: Information published.
• 2026-09-08: Updated software table to remove clients versions because this vulnerability only impacts Windows Servers. This is an informational change only.