Reference page — cumulative record through Wednesday, August 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.
Microsoft Windows 11 version 26H1 — Windows Container Isolation FS Filter Driver (unionfs.sys) Information Disclosure Vulnerability
AV AC PR UI S C I A CVSS EPSS %ile KEV
L L L N U H N N 5.5 .0030 23.1 —
AFFECTED
Product Versions Fixed
Windows 11 version 26H1 10.0.28000.0 – —
TIMELINE
Jun 4 Reserved by microsoft
Jul 14 Published (CNA: microsoft)
Jul 22 RESCORED — CVE-2026-50428 (Microsoft Windows 11 version 26H1). CVSS 7.1 → 5.5 (NVD).
Description
Out-of-bounds read in Windows Container Isolation FS Filter Driver (unionfs.sys) allows an authorized attacker to disclose information locally.
Lifecycle
Complete event history — 3 events, chronological
| Date | Event | Detail |
|---|
| June 4, 2026 | Reserved | Reserved by microsoft |
| July 14, 2026 | Published | Published (CNA: microsoft) |
| July 22, 2026 | RESCORED | RESCORED — CVE-2026-50428 (Microsoft Windows 11 version 26H1). CVSS 7.1 → 5.5 (NVD). |
Affected
Affected products and packages — 1 row
| Vendor | Product / Package | Ecosystem | Version introduced | Fixed |
|---|
| Microsoft | Windows 11 version 26H1 | — | 10.0.28000.0 | — |
About this page
This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-50428 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Wednesday, August 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.