CVE-2026-49800: Windows Web Proxy Auto-Discovery Protocol (WPAD) Elevation of Privilege Vulnerability

Overview

Severity

High (CVSS 7.8)

CVSS Vector

CVSS:3.1/AV:L/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

Less Likely

Patch Tuesday

2026-Jul

Released

2026-07-14

Description

Integer overflow or wraparound in Windows Web Proxy Auto-Discovery Protocol (WPAD) allows an authorized attacker to elevate privileges locally.

Affected Products (19)

Windows

• Windows 10 Version 1809 for 32-bit Systems
• Windows 10 Version 1809 for x64-based Systems
• Windows Server 2019
• Windows Server 2019 (Server Core installation)
• Windows Server 2022
• Windows 10 Version 21H2 for 32-bit Systems
• Windows 10 Version 21H2 for ARM64-based Systems
• Windows 10 Version 21H2 for x64-based Systems
• Windows Server 2025 (Server Core installation)
• 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 Server 2025
• Windows 11 version 26H1 for x64-based Systems
• Windows 11 Version 26H1 for ARM64-based Systems

ESU

• Windows 10 Version 22H2 for x64-based Systems
• Windows 10 Version 22H2 for ARM64-based Systems
• Windows 10 Version 22H2 for 32-bit Systems

Security Updates (7)

• 5099538
• 5099540
• 5099539
• 5099536
• 5101650
• 5095051
• 5101649

Acknowledgments

nerty with <a href="https://theori.io/">Theori</a>, <a href="https://www.z1r0.top/">z1r0</a>, Anonymous, <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>, <a href="https://x.com/_twinklestar03">TwinkleStar03</a> with <a href="https://devco.re/">DEVCORE Internship Program</a>, <a href="https://www.linkedin.com/in/brandon-fisher-666bb01b8/">Brandon Fisher</a>, <a href="https://www.linkedin.com/in/brandon-fisher-666bb01b8/">Brandon Fisher</a>, <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>, <a href="https://www.linkedin.com/in/dongjun-lee-a1505b1b1/">Dongjun Lee</a> with <a href="https://kaist-hacking.github.io/">KAIST Hacking Lab</a>, nerty with <a href="https://theori.io/">Theori</a>, nerty with <a href="https://theori.io/">Theori</a>, Anonymous, k0shl, 021w with Vulnerability Research Institute

Revision History

• 2026-07-14: Information published.