CVE-2026-97787

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

At a glance

Severity: HIGH 7.0
EPSS: EPSS 0.21 % · percentile 12 (2026-10-28)
State: PUBLISHED
Published: 2026-10-13
Updated: 2026-10-28
Assigner: microsoft
NVD status: Analyzed

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.

Scores

Version	Score	Vector	Scored by
CVSS 3.1	HIGH 7.0	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	microsoft
CVSS 3.1	HIGH 7.0	CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H	NVD · secure@microsoft.com (Secondary)

Weaknesses (CWE)

CWE-362

European references

ENISA EUVD · EUVD-2026-100309
GCVE · GCVE-0-2026-97787

CERT-FR advisories

CERTFR-2026-AVI-1314 — Multiples vulnérabilités dans Microsoft Windows · cert.ssi.gouv.fr

Affected configurations (NVD CPE)

cpe:2.3:o:microsoft:windows_11_23h2:*:*:*:*:*:*:arm64:* < 10.0.22631.7652
cpe:2.3:o:microsoft:windows_11_23h2:*:*:*:*:*:*:x64:* < 10.0.22631.7652
cpe:2.3:o:microsoft:windows_11_24h2:*:*:*:*:*:*:arm64:* < 10.0.26100.9711
cpe:2.3:o:microsoft:windows_11_24h2:*:*:*:*:*:*:x64:* < 10.0.26100.9711
cpe:2.3:o:microsoft:windows_11_25h2:*:*:*:*:*:*:arm64:* < 10.0.26200.9711
cpe:2.3:o:microsoft:windows_11_25h2:*:*:*:*:*:*:x64:* < 10.0.26200.9711
cpe:2.3:o:microsoft:windows_11_26h1:*:*:*:*:*:*:arm64:* < 10.0.28000.3231
cpe:2.3:o:microsoft:windows_11_26h1:*:*:*:*:*:*:x64:* < 10.0.28000.3231
cpe:2.3:o:microsoft:windows_11_26h2:*:*:*:*:*:*:arm64:* < 10.0.26300.9711
cpe:2.3:o:microsoft:windows_11_26h2:*:*:*:*:*:*:x64:* < 10.0.26300.9711
cpe:2.3:o:microsoft:windows_server_2022:*:*:*:*:*:*:*:* < 10.0.20348.5761
cpe:2.3:o:microsoft:windows_server_2025:*:*:*:*:*:*:x64:* < 10.0.26100.33650

Affected products

Product	Versions
Microsoft · Windows 11 version 23H2	affected 10.0.22631.0 < 10.0.22631.7652
Microsoft · Windows 11 Version 23H2	affected 10.0.22631.0 < 10.0.22631.7652
Microsoft · Windows 11 Version 24H2	affected 10.0.26100.0 < 10.0.26100.9711
Microsoft · Windows 11 Version 25H2	affected 10.0.26200.0 < 10.0.26200.9711
Microsoft · Windows 11 version 26H1	affected 10.0.28000.0 < 10.0.28000.3231
Microsoft · Windows 11 Version 26H2	affected 10.0.26300.0 < 10.0.26300.9711
Microsoft · Windows Server 2022	affected 10.0.20348.0 < 10.0.20348.5761
Microsoft · Windows Server 2025	affected 10.0.26100.0 < 10.0.26100.33650
Microsoft · Windows Server 2025 (Server Core installation)	affected 10.0.26100.0 < 10.0.26100.33650

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-97787

Sources

Source	Licence
CVE List (CVEProject cvelistV5)	CVE Program Terms of Use
EPSS (FIRST.org)	FIRST — attribution requested
ENISA EUVD	ENISA — reproduction authorised, source acknowledged
CERT-FR (ANSSI)	Licence Ouverte / Etalab 2.0
NVD (NIST) via fkie-cad/nvd-json-data-feeds	Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD