Vulnerability Report

CVE-2026-20839

Title: Improper access control in Windows Client-Side Caching (CSC) Service

Other

Proof Of Concept

No public PoC currently indexed for CVE-2026-20839.

CWE Category CWE-284

Published Date Jan 13, 2026

Modified Date Jan 15, 2026

Exploit Status Not Found

Score 5.5 CVSS v3.1

Exploit Probability (EPSS)

0.46%

Vulnerability Summary

CVE-2026-20839: Improper access control in Windows Client-Side Caching (CSC) Service allows an authorized attacker to disclose information locally.

Impacted Vendors

microsoft 14

Reference Links

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20839

CVSS v3.1

Source Entity [email protected]

Severity MEDIUM

5.5

Attack Vector

LOCAL

Complexity

LOW

Privileges

N/A

Interaction

NONE

Confidentiality

N/A

Integrity

N/A

Availability

N/A

Scope

UNCHANGED

RAW VECTOR CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

Associated Attack Patterns (CAPEC)

Total: Patterns

CVE-2026-20839 Exploits & PoCs (Proof Of Concept)

No public PoCs found in our database for this CVE.

January 15, 2026 MODIFIED

Vulnerability data updated via NVD.

January 15, 2026 MODIFIED

Vulnerability data updated via NVD.

January 14, 2026 MODIFIED

Vulnerability data updated via NVD.

January 13, 2026 MODIFIED

Vulnerability data updated via NVD.

Attack Vector Matrix

Access Vector LOCAL

Complexity LOW

Privileges N/A

Interaction NONE

CVSS Vector String


                                    CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

Affected Stack

No specific products linked.