CVE-2026-20839
Windows Client-Side Caching (CSC) Service Information Disclosure Vulnerability
Improper access control in Windows Client-Side Caching (CSC) Service allows an authorized attacker to disclose information locally.
Attack profile
How easy it is to exploit
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- None
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
Windows Client-Side Caching (CSC) Service Information Disclosure Vulnerability
Improper access control in Windows Client-Side Caching (CSC) Service allows an authorized attacker to disclose information locally.
- Record
CVE-2026-20839- CVSS 3.1
- 5.5 Medium
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C - Weakness
- CWE-284
- Updated
- 2026-11-02
EUVDEUVD-2026-2162
Improper access control in Windows Client-Side Caching (CSC) Service allows an authorized attacker to disclose information locally.
- Record
EUVD-2026-2162- CVSS 3.1
- 5.5 Medium
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-gwv7-x72m-q3cm
Improper access control in Windows Client-Side Caching (CSC) Service allows an authorized...
Improper access control in Windows Client-Side Caching (CSC) Service allows an authorized attacker to disclose information locally.
- Record
GHSA-gwv7-x72m-q3cm- CVSS 3.1
- 5.5 Medium
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N - Weakness
- CWE-284
- Updated
- 2026-11-02
NVD
Improper access control in Windows Client-Side Caching (CSC) Service allows an authorized attacker to disclose information locally.
- Record
CVE-2026-20839- CVSS 3.1
- 5.5 Medium
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N - Weakness
- CWE-284
- Updated
- 2026-11-02
Affected products
- microsoft windows 10 version 1607
- microsoft windows 10 version 1809
- microsoft windows 10 version 21h2
- microsoft windows 10 version 22h2
- microsoft windows 11 version 23h2
- microsoft windows 11 version 24h2
- microsoft windows 11 version 25h2
- microsoft windows server 2008 r2 service pack 1
- microsoft windows server 2008 r2 service pack 1 (server core installation)
- microsoft windows server 2012
- microsoft windows server 2012 (server core installation)
- microsoft windows server 2012 r2
Show 18 moreShow less
- microsoft windows server 2012 r2 (server core installation)
- microsoft windows server 2016
- microsoft windows server 2016 (server core installation)
- microsoft windows server 2019
- microsoft windows server 2019 (server core installation)
- microsoft windows server 2022
- microsoft windows server 2022, 23h2 edition (server core installation)
- microsoft windows server 2025
- microsoft windows server 2025 (server core installation)
- microsoft windows 10 1607
- microsoft windows 10 1809
- microsoft windows 10 21h2
- microsoft windows 10 22h2
- microsoft windows 11 23h2
- microsoft windows 11 24h2
- microsoft windows 11 25h2
- microsoft windows server 2008
- microsoft windows server 2022 23h2
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases, published | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-20839 is a medium vulnerability (CVSS 5.5) in Microsoft Windows 10 Version 1607, published January 13, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.48%, the 41st percentile. No source names a fixed version.