What is CVE-2026-97787?

CVE-2026-97787 is a security advisory published by Microsoft Security Response Center (MSRC) with High severity. Windows Container Isolation FS Filter Driver (unionfs.sys) Elevation of Privilege Vulnerability

Which CVE IDs does CVE-2026-97787 cover?

CVE-2026-97787 covers the following CVE IDs: CVE-2026-97787. Each CVE has its own detail page on EchelonGraph Pulse with the synthesized EG score.

What is the CVSS v3 score of CVE-2026-97787?

CVE-2026-97787 has a CVSS v3 base score of 7.0, published by Microsoft Security Response Center (MSRC).

Which products are affected by CVE-2026-97787?

CVE-2026-97787 affects 14 products, including: Windows 11 Version 23H2 for ARM64-based Systems; Windows 11 Version 23H2 for x64-based Systems; Windows 11 Version 24H2 for ARM64-based Systems; Windows 11 Version 24H2 for x64-based Systems; Windows 11 Version 25H2 for ARM64-based Systems; and others — see the full list on the advisory page.

CVE-2026-97787HighCVSS 7.0

Windows Container Isolation FS Filter Driver (unionfs.sys) Elevation of Privilege Vulnerability

Vendor

Microsoft Security Response Center (MSRC)

Published

October 13, 2026

Last Modified

—

🔗 CVE IDs covered (1)

CVE-2026-97787 →

📋 Description

Concurrent execution using shared resource with improper synchronization ('race condition') in Windows Container Isolation FS Filter Driver (unionfs.sys) allows an authorized attacker to elevate privileges locally.

🎯 Affected products14

Windows 11 Version 23H2 for ARM64-based Systems
Windows 11 Version 23H2 for x64-based Systems
Windows 11 Version 24H2 for ARM64-based Systems
Windows 11 Version 24H2 for x64-based Systems
Windows 11 Version 25H2 for ARM64-based Systems
Windows 11 Version 25H2 for x64-based Systems
Windows 11 Version 26H1 for ARM64-based Systems
Windows 11 Version 26H2 for ARM64-based Systems
Windows 11 Version 26H2 for x64-based Systems
Windows 11 version 26H1 for x64-based Systems
Windows Server 2022
Windows Server 2022 (Server Core installation)
Windows Server 2025
Windows Server 2025 (Server Core installation)

✅ Remediation

KB5126655 (Security Update) — fixed build 10.0.20348.5761 KB5127646 (Security Update) — fixed build 10.0.28000.3231 KB5126653 (Security Update) — fixed build 10.0.22631.7652 KB5127648 (Security Update) — fixed build 10.0.26100.9711 KB5127648 (Security Update) — fixed build 10.0.26200.9711 KB5127648 (Security Update) — fixed build 10.0.26300.9711 KB5126646 (Security Update) — fixed build 10.0.26100.33650

🔗 CVE IDs covered (1)

📋 Description

🎯 Affected products14

✅ Remediation

🔗 References (11)