PatchSiren cyber security CVE debrief

CVE-2026-70149 Microsoft CVE debrief

CVE-2026-70149 is a high-severity elevation of privilege vulnerability in the Windows Client Side Caching driver (csc.sys). An authorized attacker can exploit this vulnerability to disclose sensitive information locally. Multiple Windows versions and server releases are affected, including Windows 10, Windows 11, and Windows Server 2012 through 2025.

Vendor: Microsoft
Product: Windows 10 Version 1607
CVSS: HIGH 8.8
CISA KEV: Not listed in stored evidence
Original CVE published: 2026-10-13
Original CVE updated: 2026-10-13
Advisory published: 2026-10-13
Advisory updated: 2026-10-13

Who should care

Defenders and system administrators responsible for Windows systems, especially those using Windows 10, Windows 11, and Windows Server 2012 through 2025, should assess exposure and apply patches.

Why it matters

CVE-2026-70149 is a high-severity elevation of privilege vulnerability in Windows Client Side Caching driver (csc.sys). Defenders should prioritize patching affected systems to prevent potential exploitation.

Verify patch deployment for Windows Client Side Caching driver
Assess system configurations for potential exposure
Monitor for unauthorized elevation of privilege attempts
Review logs for suspicious activity related to csc.sys

Technical summary

The Windows Client Side Caching driver (csc.sys) has a high-severity elevation of privilege vulnerability, allowing authorized attackers to disclose sensitive information locally. Multiple Windows versions are affected, including Windows 10, Windows 11, and various Windows Server releases.

Defensive priority

Apply patches immediately for Windows Client Side Caching driver (csc.sys) elevation of privilege vulnerability

Recommended defensive actions

Apply patches for Windows Client Side Caching driver (csc.sys) elevation of privilege vulnerability
Verify and apply Microsoft patches for affected Windows versions
Review system configurations for exposure

Evidence notes

The CVE Program and NVD provide official records of the vulnerability. Microsoft has a patch available for this issue. Affected systems include Windows 10, Windows 11, and Windows Server 2012 through 2025. Defenders should verify patch deployment, assess system configurations for potential exposure, and monitor for unauthorized elevation of privilege attempts. Review logs for suspicious activity related to csc.sys. The information provided is based on available data and may not cover

Sources and references

Verified primary and authoritative sources

CVE-2026-70149 CVE Program record
Publisher, destination, and source semantics verified

URL: https://www.cve.org/CVERecord?id=CVE-2026-70149

CVE Program - Official CVE Program record with source-provided CVE metadata.
CVE-2026-70149 NVD vulnerability detail
Publisher, destination, and source semantics verified

URL: https://nvd.nist.gov/vuln/detail/CVE-2026-70149

NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Windows Client Side Caching driver (csc.sys) Elevation of Privilege Vulnerability
Unverified legacy reference

URL: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/70xxx/CVE-2026-70149.json

cve_program_cvelist_v5
Source reference
Unverified legacy reference

URL: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-70149

Supplemental source - vendor-advisory, patch

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.