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CVE-2026-20817: Windows Error Reporting Service Elevation of Privilege Vulnerability

• Severity: high (CVSS 7.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 5.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-01-13 · updated 2026-07-30
• Weakness: CWE-280

Description

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

Affected products

• Microsoft Windows 10: before 10.0.19044.6809 — fixed in 10.0.19044.6809
• Microsoft Windows 10: before 10.0.19045.6809 — fixed in 10.0.19045.6809
• Microsoft Windows 11: before 10.0.22631.6491 — fixed in 10.0.22631.6491
• Microsoft Windows 11: before 10.0.26100.7623 — fixed in 10.0.26100.7623
• Microsoft Windows 11 25H2: before 10.0.26200.7623 — fixed in 10.0.26200.7623
• Microsoft Windows Server 2022: before 10.0.20348.4648 — fixed in 10.0.20348.4648
• Microsoft Windows Server 2022, 23H2 Edition (Server Core installation): before 10.0.25398.2092 — fixed in 10.0.25398.2092
• Microsoft Windows Server 2025: before 10.0.26100.32230 — fixed in 10.0.26100.32230
• Microsoft Windows 10: from 10.0.19044.0 before 10.0.19044.6809 — fixed in 10.0.19044.6809
• Microsoft Windows 10: from 10.0.19045.0 before 10.0.19045.6809 — fixed in 10.0.19045.6809
• Microsoft Windows 11: from 10.0.22631.0 before 10.0.22631.6491 — fixed in 10.0.22631.6491
• Microsoft Windows 11: from 10.0.26100.0 before 10.0.26100.7623 — fixed in 10.0.26100.7623
• Microsoft Windows 11 25H2: from 10.0.26200.0 before 10.0.26200.7623 — fixed in 10.0.26200.7623
• Microsoft Windows Server 2022: from 10.0.20348.0 before 10.0.20348.4648 — fixed in 10.0.20348.4648
• Microsoft Windows Server 2022, 23H2 Edition (Server Core installation): from 10.0.25398.0 before 10.0.25398.2092 — fixed in 10.0.25398.2092
• Microsoft Windows Server 2025: from 10.0.26100.0 before 10.0.26100.32230 — fixed in 10.0.26100.32230

How to fix

Upgrade to a fixed version: Microsoft Windows 10 10.0.19044.6809; Microsoft Windows 10 10.0.19045.6809; Microsoft Windows 11 10.0.22631.6491; Microsoft Windows 11 10.0.26100.7623; Microsoft Windows 11 25H2 10.0.26200.7623; Microsoft Windows Server 2022 10.0.20348.4648; Microsoft Windows Server 2022, 23H2 Edition (Server Core installation) 10.0.25398.2092; Microsoft Windows Server 2025 10.0.26100.32230; Microsoft Windows 10 10.0.19044.6809; Microsoft Windows 10 10.0.19045.6809; Microsoft Windows 11 10.0.22631.6491; Microsoft Windows 11 10.0.26100.7623. Check the vendor advisory for mitigations.

References

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20817
• https://www.vicarius.io/vsociety/posts/cve-2026-20817-detection-script-eop-vulnerabilit-in-windows-error-reporting
• https://www.vicarius.io/vsociety/posts/cve-2026-20817-mitigation-script-eop-vulnerability-in-windows-error-reporting

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