What is CVE-2026-20830?

CVE-2026-20830 is a high-severity vulnerability in Microsoft Windows Server 2025, classified under Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition). CVSS score: 7.0/10. Published 2026-01-13.

How severe is CVE-2026-20830?

High severity. CVSS v3 base score is 7.0 out of 10.

Use After Free in Microsoft Windows Server 2025

CVE-2026-20830

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

Vulnerability class: Race Condition

Published 2026-01-13 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.0 (High). Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.003 (20.3th percentile), scored 2026-10-02.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 20th percentile — 20.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: -0.000

Affected products

Microsoft Windows Server 2025 — versions 10.0.26100.0
Microsoft Windows Server 2025
Microsoft Windows Server 2025 (Server Core Installation) — versions 10.0.26100.0

Weakness classification (CWE)

References

Capability Access Management Service (camsvc) Elevation of Privilege Vulnerability (vendor-advisory, patch, Vendor Advisory)

Frequently asked questions

What is CVE-2026-20830?: CVE-2026-20830 is a high-severity vulnerability in Microsoft Windows Server 2025, classified under Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition). CVSS score: 7.0/10. Published 2026-01-13.
How severe is CVE-2026-20830?: High severity. CVSS v3 base score is 7.0 out of 10.