Heap-based buffer overflow in Microsoft Windows and Windows Server - CVE-2026-83777

Vulnerability identifier: #VU154939

CSH Severity: High

CVSS v4: 8.7 [CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-83777

CWE-ID: CWE-122

Exploitation vector: Adjecent network

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to gain SYSTEM privileges.

The vulnerability exists due to a heap-based buffer overflow in Windows Bluetooth Service when accessed over an adjacent network. A remote attacker can exploit this flaw to gain SYSTEM privileges.

Microsoft Windows
Windows Server

Install security update from vendor's website.

Microsoft Windows - addressed in versions 10 21H2 10.0.19044.7807, 10 1607 10.0.14393.9612, 10 1809 10.0.17763.9376, 11 23H2 10.0.22631.7652, 11 24H2 10.0.26100.9711, 11 25H2 10.0.26200.9711, 11 26H1 10.0.28000.3231
Windows Server - addressed in versions 2016 10.0.14393.9612, 2019 10.0.17763.9376, 2022 10.0.20348.5761, 2025 10.0.26100.33650

• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2026-83777
• https://support.microsoft.com/help/5126651

• Multiple vulnerabilities in Microsoft Windows