Stack-based buffer overflow in Microsoft products - CVE-2026-50387

Vulnerability identifier: #VU138030

CSH Severity: Low

CVSS v4: 8.5 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-50387

CWE-ID: CWE-121

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local user to escalate privileges.

The vulnerability exists due to stack-based buffer overflow in Windows GDI when parsing input. A local user can trigger the flaw to escalate privileges.

Successful exploitation could allow the attacker to gain SYSTEM privileges.

Microsoft Office for macOS
Microsoft Office for Android
Microsoft Windows
Windows Server

Install security update from vendor's website.

Microsoft Office for macOS - update to 16.111.26071215
Microsoft Office for Android - update to 16.0.20228.20042
Microsoft Windows - addressed in versions 10 21H2 10.0.19044.7548, 10 22H2 10.0.19045.7548, 10 1607 10.0.14393.9339, 10 1809 10.0.17763.9020, 11 24H2 10.0.26100.8875, 11 25H2 10.0.26200.8875, 11 26H1 10.0.28000.2269, 11 26H1 10.0.28000.2525
Windows Server - addressed in versions 2012 R2 6.3.9600.23291, 2012 6.2.9200.26226, 2016 10.0.14393.9339, 2019 10.0.17763.9020, 2022 10.0.20348.5386, 2025 10.0.26100.33158

• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2026-50387

• Multiple vulnerabilities in Microsoft Windows