CVE-2026-21221: Capability Access Management Service (camsvc) Elevation of Privilege Vulnerability

Overview

Severity

High (CVSS 7)

CVSS Vector

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

Category

Elevation of Privilege

Exploit Status

Not Exploited

Exploitation Likelihood

Unlikely

Patch Tuesday

2026-Jan

Released

2026-01-13

Last Updated

2026-01-20

EPSS Score

0.05% (percentile: 14.5%)

Description

Concurrent execution using shared resource with improper synchronization ('race condition') in Capability Access Management Service (camsvc) allows an authorized attacker to elevate privileges locally.

FAQ

According to the CVSS metric, the attack complexity is high (AC:H). What does that mean for this vulnerability? Successful exploitation of this vulnerability requires an attacker to win a race condition. What privileges could be gained by an attacker who successfully exploited this vulnerability? An attacker who successfully exploited this vulnerability could gain SYSTEM privileges.

Affected Products (6)

Windows

• 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

Security Updates (2)

• 5073379
• 5074109

Acknowledgments

<a href="https://twitter.com/keyz3r0">k0shl</a>

Revision History

• 2026-01-13: Information published.
• 2026-01-20: Updated the build numbers. This is an informational update only.