Use of uninitialized resource in Microsoft Windows and Windows Server - CVE-2026-88247

Vulnerability identifier: #VU165583

CSH Severity: Low

CVSS v4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-88247

CWE-ID: CWE-908

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local user to disclose sensitive information from uninitialized stack memory.

The vulnerability exists due to use of an uninitialized resource in Windows Program Compatibility Assistant Service when accessing stack memory before initialization. A local user can exploit this condition locally to read stack memory that may contain sensitive information.

Microsoft Windows
Windows Server

Install security update from vendor's website.

Microsoft Windows - addressed in versions 10 21H2 10.0.19044.7846, 10 22H2 10.0.19045.7846, 10 1607 10.0.14393.9688, 10 1809 10.0.17763.9487, 11 23H2 10.0.22631.7711, 11 24H2 10.0.26100.9911, 11 24H2 10.0.26100.9974, 11 25H2 10.0.26200.9911, 11 25H2 10.0.26200.9974, 11 26H1 10.0.28000.3501
Windows Server - addressed in versions 2016 10.0.14393.9688, 2019 10.0.17763.9487, 2022 10.0.20348.5870, 2025 10.0.26100.33730, 2025 10.0.26100.33822

• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2026-88247
• https://support.microsoft.com/help/5131291

• Multiple vulnerabilities in Microsoft Windows