CVE-2026-70149: Windows Client Side Caching driver (csc.sys) Elevation of Privilege Vulnerability

Overview

Severity
High (CVSS 8.8)
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
Category
Elevation of Privilege
Exploit Status
Not Exploited
Exploitation Likelihood
Less Likely
Patch Tuesday
2026-Oct
Released
2026-10-13

Description

Exposure of sensitive information to an unauthorized actor in Windows Client Side Caching driver (csc.sys) allows an authorized attacker to disclose information locally.

FAQ

What privileges could be gained by an attacker who successfully exploited this vulnerability? An attacker who successfully exploited this vulnerability could gain SYSTEM privileges. How could an attacker exploit this vulnerability? An attacker could host a malicious server and convince a user to connect to it from an affected client. When the client processes the server's response, the attacker could execute code on the client system. User interaction is required.

Affected Products (32)

ESU

  • Windows Server 2012
  • Windows Server 2012 (Server Core installation)
  • Windows Server 2012 R2
  • Windows Server 2012 R2 (Server Core installation)
  • Windows 10 Version 22H2 for 32-bit Systems
  • Windows 10 Version 22H2 for ARM64-based Systems
  • Windows 10 Version 22H2 for x64-based Systems

Windows

  • Windows 10 Version 1607 for 32-bit Systems
  • Windows 10 Version 1607 for x64-based Systems
  • Windows Server 2016
  • Windows Server 2016 (Server Core installation)
  • 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 10 Version 21H2 for 32-bit Systems
  • Windows 10 Version 21H2 for ARM64-based Systems
  • Windows 10 Version 21H2 for x64-based Systems
  • Windows Server 2022
  • Windows Server 2022 (Server Core installation)
  • Windows 11 Version 24H2 for ARM64-based Systems
  • Windows 11 Version 24H2 for x64-based Systems
  • Windows 11 Version 25H2 for ARM64-based Systems
  • Windows 11 Version 25H2 for x64-based Systems
  • Windows 11 Version 26H2 for ARM64-based Systems
  • Windows 11 Version 26H2 for x64-based Systems
  • Windows Server 2025
  • Windows Server 2025 (Server Core installation)
  • Windows 11 Version 23H2 for ARM64-based Systems
  • Windows 11 Version 23H2 for x64-based Systems
  • Windows 11 Version 26H1 for ARM64-based Systems
  • Windows 11 version 26H1 for x64-based Systems

Security Updates (10)

Acknowledgments

<a href="https://github.com/cbwang505">ChengBin Wang</a> with <a href="https://www.guolisec.com/">ZheJiang Guoli Security Technology</a>

Revision History

  • 2026-10-13: Information published.