CVE-2026-72971: exploitation status and patch state

CVE-2026-72971 · CVSS 5.5 MEDIUM · patch available

Improper link resolution before file access ('link following') in Windows Container Isolation FS Filter Driver (unionfs.sys) allows an authorized attacker to perform tampering locally.

Is CVE-2026-72971 exploited?

• Not in the CISA KEV catalog.
• Public exploit code: none found in monitored sources.

Which products and versions are affected?

• Microsoft · Windows 11 Version 26H1 for ARM64-based Systems · < 10.0.28000.2704
• Microsoft · Windows 11 version 26H1 for x64-based Systems · < 10.0.28000.2704

Is there a patch?

• KB5121000

What PlainSec published about CVE-2026-72971

• Adobe and Microsoft Ship Huge August Patch Loads (2026-08-12)

Primary sources

• NVD record
• Microsoft KB5121000

What this record does not say

• No EPSS score.

KEV and EPSS are re-checked daily. Record last updated 2026-08-25.