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CVE-2026-65776 Microsoft CVE debrief

The CVE-2026-65776 vulnerability is a high-severity elevation of privilege issue in Windows Win32K, allowing an authorized attacker to elevate privileges locally. This vulnerability affects Windows 11 Version 24H2, Windows 11 Version 25H2, Windows 11 version 26H1, Windows Server 2025, and Windows Server 2025 (Server Core installation). Defenders should prioritize verifying exposure and applying patches to prevent local privilege escalation. The CVE record was published on 2026-08-11T17:06:52.067Z and has not been modified since then.

Vendor
Microsoft
Product
Windows 11 Version 24H2
CVSS
HIGH 7
CISA KEV
Not listed in stored evidence
Original CVE published
2026-08-11
Original CVE updated
2026-10-08
Advisory published
2026-08-11
Advisory updated
2026-10-08

Who should care

Defenders responsible for Windows systems, particularly those managing Windows 11 and Windows Server 2025 deployments, should assess exposure and apply patches.

Why it matters

CVE-2026-65776 is a high-severity elevation of privilege vulnerability in Windows Win32K. Defenders should prioritize verifying exposure and applying patches to prevent local privilege escalation.

  • Verify exposure of Windows 11 Version 24H2, Windows 11 Version 25H2, Windows 11 version 26H1, Windows Server 2025, and Windows Server 2025 (Server Core installation) systems
  • Apply patches or compensating controls to prevent local privilege escalation
  • Monitor for indicators of compromise or exploitation attempts

Technical summary

The vulnerability is a use-after-free issue in Windows Win32K that allows an authorized attacker to elevate privileges locally. This issue affects Windows 11 Version 24H2, Windows 11 Version 25H2, Windows 11 version 26H1, Windows Server 2025, and Windows Server 2025 (Server Core installation). Defenders should prioritize verifying exposure and applying patches to prevent local privilege escalation.

Defensive priority

Defenders should prioritize verifying exposure and applying patches for Windows 11 Version 24H2, Windows 11 Version 25H2, Windows 11 version 26H1, Windows Server 2025, and Windows Server 2025 (Server Core installation) systems.

Recommended defensive actions

  • Verify system inventory for affected Windows versions
  • Apply patches from Microsoft
  • Monitor for local privilege escalation attempts

Evidence notes

The CVE record and source item provide details on the vulnerability, but limited information is available on exploitation or impact. Defenders should verify exposure of affected Windows versions and apply patches or compensating controls to prevent local privilege escalation. The source item and CVE record do not provide explicit evidence of exploitation or specific impact, so defenders should exercise caution and monitor for indicators of compromise.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-65776 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-65776

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

  • CVE-2026-65776 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-65776

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

Supplemental references

  • Windows Win32k Elevation of Privilege Vulnerability

    Unverified legacy reference

    URL: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/65xxx/CVE-2026-65776.json

    cve_program_cvelist_v5

  • Source reference

    Unverified legacy reference

    URL: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-65776

    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.