Microsoft Security Response CenterCVE-2026-20823

Windows File Explorer Information Disclosure Vulnerability

Exposure of sensitive information to an unauthorized actor in Windows File Explorer allows an authorized attacker to disclose information locally.

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5.5CVSS out of 10High severity

Scope

What the vendor says is affected

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 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 10 Version 22H2 for x64-based Systems
Windows 10 Version 22H2 for ARM64-based Systems
Windows 10 Version 22H2 for 32-bit 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
Windows 10 Version 1607 for 32-bit Systems
Windows 10 Version 1607 for x64-based Systems
Windows Server 2016

Versions the vendor lists as fixed

10.0.17763.8276
10.0.20348.4648
10.0.19044.6809
10.0.19045.6809
10.0.26100.32230
10.0.26200.7623
10.0.22631.6491
10.0.25398.2092
10.0.26100.7623
10.0.14393.8783

Next step

What the vendor recommends

Install KB5073723. Install KB5073457. Install KB5073724. Install KB5073379. Install KB5074109. Install KB5073455. Install KB5073450. Install KB5073722.

Review the complete instructions on the vendor's site

Timeline

When this advisory changed

Jan 13, 2026 at 8:00 AM UTC
Published by Microsoft Security Response Center
The publication date reported by the vendor.
May 12, 2026 at 7:00 AM UTC
Updated by Microsoft Security Response Center
The vendor changed the advisory after it was first published.
Sep 29, 2026 at 11:40 AM UTC
Added to SecurityAlert
We collected the advisory from the official source.

Vulnerabilities

CVEs named in this advisory

CVE-2026-20823View CVSS, KEV, EPSS, and threat context

Source

Start with the vendor's bulletin

SecurityAlert organizes the fields the vendor published. The original bulletin remains the source of record for affected versions, fixes, and later changes.

Vendor: Microsoft Security Response Center
Advisory ID: CVE-2026-20823
Last source check: Sep 29, 2026 at 11:40 AM UTC

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What the vendor says is affected

Versions the vendor lists as fixed

What the vendor recommends

When this advisory changed

CVEs named in this advisory

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