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CVE-2026-45487 Microsoft CVE debrief

CVE-2026-45487 is a HIGH severity vulnerability with a CVSS score of 7.8. It was published on 2026-06-09T17:17:24.403Z and modified on 2026-06-11T15:35:20.493Z. The vulnerability is a Time-of-check time-of-use (TOCTOU) race condition in Program Compatibility Assistant Service, which allows an authorized attacker to elevate privileges locally. The affected products include various versions of Windows 10, Windows 11, Windows Server 2022, and Windows Server 2025.

Vendor
Microsoft
Product
Windows 10 Version 21H2
CVSS
HIGH 7.8
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-09
Original CVE updated
2026-06-11
Advisory published
2026-06-09
Advisory updated
2026-06-11

Who should care

Administrators and users of affected Microsoft Windows versions should prioritize patching this vulnerability to prevent local privilege escalation attacks.

Technical summary

The vulnerability is caused by a Time-of-check time-of-use (TOCTOU) race condition in Program Compatibility Assistant Service. This allows an authorized attacker to elevate privileges locally. The Common Vulnerability Scoring System (CVSS) vector is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

Defensive priority

High

Recommended defensive actions

  • Apply patches from Microsoft as soon as possible.
  • Ensure that all affected systems are updated with the latest security patches.
  • Consider implementing additional security measures such as monitoring for suspicious activity and restricting access to sensitive areas of the system.

Evidence notes

The CVE record and details are sourced from official databases and vendor advisories.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-45487 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-45487

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

  • CVE-2026-45487 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-45487

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

Supplemental references

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.