CVE-2026-20839

Severity CVSS v4.0:

Pending analysis

Type:

CWE-284 Improper Access Control

Publication date:

13/01/2026

Last modified:

13/01/2026

Description

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

Impact

Vector 3.x

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N CVSS v3.1 Severity and Metrics:

Base Score: 5.50 MEDIUM
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

Attack Vector (AV): Local
Attack Complexity (AC): Low
Privileges Required (PR): Low
User Interaction (UI): None
Scope (S): Unchanged
Confidentiality (C): High
Integrity (I): None
Availability (A): None

Base Score 3.x

5.50

Severity 3.x

MEDIUM

References to Advisories, Solutions, and Tools

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