PT-2026-2689 · Microsoft · Windows Client-Side Caching (Csc) Service+1

Published 2026-01-13 · Updated 2026-01-15 · CVE-2026-20839

Positive Technologies (AI Summary)

CVSS v3.1

5.5

Medium

Base vector

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

Name of the Vulnerable Software and Affected Versions Windows Client-Side Caching (CSC) Service (affected versions not specified)

Description An issue with access control in the Windows Client-Side Caching (CSC) Service can allow an attacker to disclose information locally. The vulnerability allows attackers to obtain sensitive information and affect the system.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.

Improper Access Control

Weakness Enumeration

CWE-284

Related Identifiers

BDU:2026-00425

CVE-2026-20839

Affected Products

Windows

Windows Client-Side Caching (Csc) Service

References · 7

• https://osv.dev/vulnerability/CVE-2026-20839 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-20839 · Security Note
• http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-20839 · Security Note
• https://bdu.fstec.ru/vul/2026-00425 · Security Note
• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20839 · Vendor Advisory
• https://msrc.microsoft.com/update-guide/en-US/advisory/CVE-2026-20839 · Vendor Advisory
• https://twitter.com/CVEnew/status/2011759676283617299 · Twitter Post