CVE-2026-20839HighCVSS 5.5

Windows Client-Side Caching (CSC) Service Information Disclosure Vulnerability

Published
June 2, 2026
Last Modified
—

🔗 CVE IDs covered (1)

CVE-2026-20839 →

📋 Description

Improper access control in Windows Client-Side Caching (CSC) Service allows an authorized attacker to disclose information locally.

🎯 Affected products31

  • Windows 10 Version 1607 for 32-bit Systems
  • Windows 10 Version 1607 for x64-based Systems
  • Windows 10 Version 1809 for 32-bit Systems
  • Windows 10 Version 1809 for x64-based Systems
  • 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 32-bit Systems
  • Windows 10 Version 22H2 for ARM64-based Systems
  • Windows 10 Version 22H2 for x64-based Systems
  • Windows 11 Version 23H2 for ARM64-based Systems
  • Windows 11 Version 23H2 for x64-based Systems
  • Windows 11 Version 24H2 for ARM64-based Systems
  • Windows 11 Version 24H2 for x64-based Systems
  • Windows 11 Version 25H2 for ARM64-based Systems
  • Windows 11 Version 25H2 for x64-based Systems
  • Windows Server 2008 R2 for x64-based Systems Service Pack 1
  • Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation)
  • Windows Server 2012
  • Windows Server 2012 (Server Core installation)
  • Windows Server 2012 R2
  • Windows Server 2012 R2 (Server Core installation)
  • Windows Server 2016
  • Windows Server 2016 (Server Core installation)
  • Windows Server 2019
  • Windows Server 2019 (Server Core installation)
  • Windows Server 2022
  • Windows Server 2022 (Server Core installation)
  • Windows Server 2022, 23H2 Edition (Server Core installation)
  • Windows Server 2025
  • +1 more not shown

✅ Remediation

KB5073723 (Security Update) — fixed build 10.0.17763.8276 KB5073457 (Security Update) — fixed build 10.0.20348.4648 KB5073724 (Security Update) — fixed build 10.0.19044.6809 KB5073724 (Security Update) — fixed build 10.0.19045.6809 KB5073379 (Security Update) — fixed build 10.0.26100.32230 KB5074109 (Security Update) — fixed build 10.0.26200.7623 KB5073455 (Security Update) — fixed build 10.0.22631.6491 KB5073450 (Security Update) — fixed build 10.0.25398.2092 KB5074109 (Security Update) — fixed build 10.0.26100.7623 KB5073722 (Security Update) — fixed build 10.0.14393.8783 KB5073695 (Monthly Rollup) — fixed build 6.1.7601.28117 KB5073699 (Security Only) — fixed build 6.1.7601.28117 KB5073698 (Monthly Rollup) — fixed build 6.2.9200.25868 KB5073696 (Monthly Rollup) — fixed build 6.3.9600.22968

🔗 References (26)