Heap-based buffer overflow in Microsoft Windows and Windows Server - CVE-2026-49178

Vulnerability identifier: #VU137962

CSH Severity: Medium

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

CVE-ID: CVE-2026-49178

CWE-ID: CWE-122

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote user to execute arbitrary code.

The vulnerability exists due to a heap-based buffer overflow in the NSPI RPC interface in Active Directory Domain Services when processing crafted inputs. A remote user can send crafted RPC inputs to execute arbitrary code.

Exploitation requires domain authentication and does not require user interaction.

Microsoft Windows
Windows Server

Install security update from vendor's website.

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-2026-49178

• Multiple vulnerabilities in Microsoft Windows