Description
Improper handling of insufficient permissions or privileges in Windows Error Reporting allows an authorized attacker to elevate privileges locally.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Microsoft | Windows 10 Version 21H2 | 10.0.19044.0 – < 10.0.19044.6809 | 10.0.19044.6809 |
| Microsoft | Windows 10 Version 22H2 | 10.0.19045.0 – < 10.0.19045.6809 | 10.0.19045.6809 |
| Microsoft | Windows 11 version 23H2 | 10.0.22631.0 – < 10.0.22631.6491 | 10.0.22631.6491 |
| Microsoft | Windows 11 Version 24H2 | 10.0.26100.0 – < 10.0.26100.7623 | 10.0.26100.7623 |
| Microsoft | Windows 11 Version 25H2 | 10.0.26200.0 – < 10.0.26200.7623 | 10.0.26200.7623 |
| Microsoft | Windows Server 2022 | 10.0.20348.0 – < 10.0.20348.4648 | 10.0.20348.4648 |
| Microsoft | Windows Server 2022, 23H2 Edition (Server Core installation) | 10.0.25398.0 – < 10.0.25398.2092 | 10.0.25398.2092 |
| Microsoft | Windows Server 2025 | 10.0.26100.0 – < 10.0.26100.32230 | 10.0.26100.32230 |
| Microsoft | Windows Server 2025 (Server Core installation) | 10.0.26100.0 – < 10.0.26100.32230 | 10.0.26100.32230 |
Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
Third-party code, not reviewed by us. Public PoCs are sometimes fake or contain malware. Read the code first and run it only in an isolated lab, against systems you are authorised to test.
GitHub 2 repositories
-
oxfemale/CVE-2026-20817 ★ 132 · Feb 18, 2026
Windows Error Reporting ALPC Elevation of Privilege (CVE-2026-20817) - Proof-of-Concept exploit demonstrating local privilege escalation via WER service.
-
dwgth4i/CVE-2026-20817 ★ 0 · May 28, 2026
PoC for CVE-2026-20817
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Advisories 3
- NCSC-2026-0007 Kwetsbaarheden verholpen in Microsoft Windows NCSC-NL (Netherlands) · Apr 10, 2026
- WID-SEC-2026-0083 Microsoft Windows : Mehrere Schwachstellen BSI CERT-Bund (WID) · Mar 2, 2026
- MSRC-CVE-2026-20817 Windows Error Reporting Service Elevation of Privilege Vulnerability Microsoft Security Response Center · Jan 13, 2026
References
- Windows Error Reporting Service Elevation of Privilege Vulnerability vendor-advisory patch