CVE-2026-55144: Windows Cryptography API: Next Generation (CNG) Tampering Vulnerability

Overview

Severity

High (CVSS 7.1)

CVSS Vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N/E:U/RL:O/RC:C

Category

Tampering

Exploit Status

Not Exploited

Exploitation Likelihood

Unlikely

Patch Tuesday

2026-Jul

Released

2026-07-14

Description

Missing cryptographic step in Windows CryptoAPI allows an authorized attacker to perform tampering locally.

Affected Products (9)

Windows

• Windows Server 2022
• Windows Server 2025 (Server Core installation)
• Windows 11 Version 25H2 for ARM64-based Systems
• Windows 11 Version 25H2 for x64-based Systems
• Windows 11 Version 24H2 for ARM64-based Systems
• Windows 11 Version 24H2 for x64-based Systems
• Windows Server 2025
• Windows 11 version 26H1 for x64-based Systems
• Windows 11 Version 26H1 for ARM64-based Systems

Security Updates (4)

• 5099540
• 5099536
• 5101650
• 5101649

Acknowledgments

Samuel Lee with Microsoft, Samuel Lee with Microsoft

Revision History

• 2026-07-14: Information published.