Heap-based buffer overflow in Microsoft Windows and Windows Server - CVE-2026-62753

Vulnerability identifier: #VU141538

CSH Severity: Low

CVSS v4: 7.3 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-62753

CWE-ID: CWE-122

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local user to escalate privileges on the target system.

The vulnerability exists due to a boundary error in Windows HTTP.sys. A local user can pass specially crafted data to the application, trigger a heap-based buffer overflow and gain elevated privileges on the system.

Microsoft Windows
Windows Server

Install updates from vendor's website.

Microsoft Windows - addressed in versions 10 21H2 10.0.19044.7663, 10 22H2 10.0.19045.7663, 10 1607 10.0.14393.9418, 10 1809 10.0.17763.9115, 11 23H2 10.0.22631.7517, 11 24H2 10.0.26100.9106, 11 24H2 10.0.26100.9168, 11 25H2 10.0.26200.9168, 11 26H1 10.0.28000.2704
Windows Server - addressed in versions 2012 R2 6.3.9600.23337, 2012 6.2.9200.26279, 2016 10.0.14393.9418, 2019 10.0.17763.9115, 2022 10.0.20348.5440, 2022 10.0.20348.5499, 2025 10.0.26100.33222, 2025 10.0.26100.33296

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-62753

• Multiple vulnerabilities in Microsoft Windows HTTP.sys