MEDIUM 5.5 Microsoft
CVE-2026-20839
Windows Client-Side Caching (CSC) Service Information Disclosure Vulnerability
Microsoft Security Update 2026-Jan: Windows Client-Side Caching (CSC) Service Information Disclosure Vulnerability
Affected Products
- 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
References
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20839
- https://nvd.nist.gov/vuln/detail/CVE-2026-20839
This medium severity vulnerability with a CVSS score of 5.5 was published on 2026-01-13 via Microsoft. Affected: Windows 10 Version 1809 for 32-bit Systems, Windows 10 Version 1809 for x64-based Systems, Windows Server 2019 and 5 more.
vulnfeed aggregates 9166 vulnerabilities from NVD, CISA KEV,
Ubuntu, Debian, Red Hat, Kubernetes, Exploit-DB, OSS-Security, GitHub and OpenStack — updated every 4 hours.