CVE-2026-87699

7.8High

Published 13 Oct 2026 · NVD status: Undergoing Analysis · AI triage by gemini-3.8-flash

7.8High

Attack vector: Local
Complexity: Low
Privileges needed: Low
User interaction: None
Impact: Full C/I/A compromise
Weakness: CWE-122

Impact

Local authenticated attackers can execute arbitrary code with elevated privileges, likely SYSTEM, on the target machine. They need existing local user access to trigger the flaw.

Root cause

A heap-based buffer overflow exists within the Windows Winlogon component.

Affected systems

Versions not listed — check the vendor advisory.

CVSS v3.1 · CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Fix & remediation

Install the relevant Microsoft security update covering CVE-2026-87699 from the MSRC advisory. No documented interim mitigation exists.

AI-suggested. Run it in staging first and check it against the vendor advisory. Why?

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NVD description

Heap-based buffer overflow in Winlogon allows an authorized attacker to elevate privileges locally.

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-87699

Source: nvd.nist.gov/vuln/detail/CVE-2026-87699