CVE-2026-97790

Windows Container Isolation FS Filter Driver (unionfs.sys) Tampering Vulnerability

At a glance

Severity: MEDIUM 5.5
EPSS: EPSS 0.39 % · percentile 32 (2026-10-27)
State: PUBLISHED
Published: 2026-10-13
Updated: 2026-10-28
Assigner: microsoft
NVD status: Analyzed

Description

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.

Scores

Version	Score	Vector	Scored by
CVSS 3.1	MEDIUM 5.5	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N/E:U/RL:O/RC:C	microsoft
CVSS 3.1	MEDIUM 5.5	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N	NVD · secure@microsoft.com (Secondary)

Weaknesses (CWE)

CWE-59

European references

ENISA EUVD · EUVD-2026-100310
GCVE · GCVE-0-2026-97790

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_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 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-2026-97790

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