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CVE-2026-85920 Microsoft CVE debrief

A time-of-check time-of-use (TOCTOU) race condition vulnerability in Windows BitLocker allows an authorized attacker to elevate privileges locally. Multiple Windows versions are affected, including Windows 10, Windows 11, and Windows Server. This vulnerability has significant implications for system administrators and security teams. The CVE Program and NVD provide official records of the vulnerability. Microsoft has released a patch for the vulnerability. Affected product deployments should be reviewed for exposure, and owners should be assigned for follow-up. Official advisories and CVE records should be consulted to validate affected scope, severity, and vendor guidance.

Vendor
Microsoft
Product
Windows 10 Version 1607
CVSS
HIGH 7
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

System administrators and security teams responsible for Windows systems, especially those using BitLocker for encryption, should apply patches immediately to prevent exploitation. These teams should review compensating controls for exposed systems while remediation is scheduled and verified. Monitoring, detection, and logs for exposed assets should be checked for extra review.

Why it matters

CVE-2026-85920 is a high-severity vulnerability in Windows BitLocker that allows local privilege escalation. System administrators and security teams should apply patches immediately to prevent exploitation.

  • Local privilege escalation is possible
  • Patching is required to prevent exploitation
  • Verify Windows versions and update to the latest

Technical summary

The vulnerability is caused by a time-of-check time-of-use (TOCTOU) race condition in Windows BitLocker, allowing an authorized attacker to elevate privileges locally. This vulnerability affects multiple Windows versions, including Windows 10, Windows 11, and Windows Server. The CVE Program and NVD provide official records of the vulnerability. Microsoft has released a patch for the vulnerability.

Defensive priority

Apply patches immediately for Windows BitLocker to prevent local privilege escalation.

Recommended defensive actions

  • Apply patches for Windows BitLocker
  • Verify and update Windows versions to the latest
  • Monitor for unusual activity related to BitLocker

Evidence notes

The CVE Program and NVD provide official records of the vulnerability. Microsoft has released a patch for the vulnerability. Evidence is limited to publicly available information from these sources. Defenders should verify the vulnerability's existence and scope within their environments. The official CVE Program record and NVD detail page provide source-provided CVE metadata and vulnerability assessment.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-85920 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-85920

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-85920 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-85920

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

Supplemental references

  • Windows BitLocker Elevation of Privilege Vulnerability

    Unverified legacy reference

    URL: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/85xxx/CVE-2026-85920.json

    cve_program_cvelist_v5

  • Source reference

    Unverified legacy reference

    URL: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-85920

    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.