CVE-2026-69777: Windows DHCP Client Elevation of Privilege Vulnerability

Overview

Severity

High (CVSS 8)

CVSS Vector

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

Category

Elevation of Privilege

Exploit Status

Not Exploited

Exploitation Likelihood

More Likely

Patch Tuesday

2026-Sep

Released

2026-09-08

Last Updated

2026-09-09

EPSS Score

0.58% (percentile: 46.8%)

Description

Heap-based buffer overflow in Windows DHCP Client allows an authorized attacker to elevate privileges over an adjacent network.

FAQ

What privileges could be gained by an attacker who successfully exploited the vulnerability? An attacker could use this vulnerability to elevate privileges from Medium Integrity Level to Local Service.

Affected Products (6)

Windows

• Windows 11 Version 25H2 for ARM64-based Systems
• Windows 11 Version 25H2 for x64-based Systems
• Windows 11 Version 24H2 for ARM64-based Systems
• Windows 11 Version 24H2 for x64-based Systems
• Windows 11 version 26H1 for x64-based Systems
• Windows 11 Version 26H1 for ARM64-based Systems

Security Updates (2)

• 5124008
• 5124012

Acknowledgments

Thanatos Tian (HKPolyU) with Diffract and HYL, <a href="https://www.linkedin.com/in/dongjun-lee-a1505b1b1/">Dongjun Lee (m0nd2y)</a> with <a href="https://kaist-hacking.github.io/">KAIST Hacking Lab</a>

Revision History

• 2026-09-08: Information published.
• 2026-09-09: Updated an acknowledgement. This is an informational change only.