CVE-2026-20817: Windows Error Reporting Service 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

More Likely

Patch Tuesday

2026-Jan

Released

2026-01-13

EPSS Score

0.02% (percentile: 6.1%)

Description

Improper handling of insufficient permissions or privileges in Windows Error Reporting allows an authorized attacker to elevate privileges locally.

FAQ

What privileges could be gained by an attacker who successfully exploited this vulnerability? An attacker who successfully exploited this vulnerability could gain SYSTEM privileges.

Detection & Weaponization (1 sources)

Maturity: Exploit

• GitHub PoC: 1 repositories

Affected Products (17)

Windows

• Windows Server 2022
• Windows Server 2022 (Server Core installation)
• 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 23H2 for ARM64-based Systems
• Windows 11 Version 23H2 for x64-based Systems
• Windows Server 2022, 23H2 Edition (Server Core installation)
• Windows 11 Version 24H2 for ARM64-based Systems
• Windows 11 Version 24H2 for x64-based Systems
• Windows Server 2025

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 (6)

• 5073457
• 5073724
• 5073379
• 5074109
• 5073455
• 5073450

Acknowledgments

Ruslan Sayfiev with <a href="https://gmo-cybersecurity.com/">GMO Cybersecurity by Ierae</a>, Denis Faiustov with <a href="https://gmo-cybersecurity.com/">GMO Cybersecurity by Ierae</a>

Revision History

• 2026-01-13: Information published.