Link following in Windows Container Isolation FS Filter Driver allows tampering
Priority LOW 25CWE-59Published · Updated
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- None · High · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA.
Summary
Improper link resolution before file access in the Windows Container Isolation FS Filter Driver (unionfs.sys) affects Windows 11 versions 24H2, 25H2, 26H1 and 26H2 and Windows Server 2022 and 2025. The flaw (CWE-59) lets an authorized local attacker with low privileges tamper with files on the system. Exploitation requires no user interaction.
Written with Claude Haiku 5.5 from the sources below · 2026-10-28
Description from the CNA
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.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00385 32nd percentileScored 2026-11-07
Fix Fixed Windows 11 Version 24H2 (Microsoft): 10.0.26100.9711Windows 11 Version 25H2 (Microsoft): 10.0.26200.9711+5 more products
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Microsoft | Windows 11 Version 24H2 | 10.0.26100.0 to before 10.0.26100.9711 | 10.0.26100.9711 | Patch available | CNA |
| Microsoft | Windows 11 Version 25H2 | 10.0.26200.0 to before 10.0.26200.9711 | 10.0.26200.9711 | Patch available | CNA |
| Microsoft | Windows 11 version 26H1 | 10.0.28000.0 to before 10.0.28000.3231 | 10.0.28000.3231 | Patch available | CNA |
| Microsoft | Windows 11 Version 26H2 | 10.0.26300.0 to before 10.0.26300.9711 | 10.0.26300.9711 | Patch available | CNA |
| Microsoft | Windows Server 2022 | 10.0.20348.0 to before 10.0.20348.5761 | 10.0.20348.5761 | Patch available | CNA |
| Microsoft | Windows Server 2025 | 10.0.26100.0 to before 10.0.26100.33650 | 10.0.26100.33650 | Patch available | CNA |
| Microsoft | Windows Server 2025 (Server Core installation) | 10.0.26100.0 to before 10.0.26100.33650 | 10.0.26100.33650 | Patch available | CNA |
- Windows 11 Version 24H2 VendorMicrosoft Affected 10.0.26100.0 to before 10.0.26100.9711 Fixed in 10.0.26100.9711 Patch available CNA
- Windows 11 Version 25H2 VendorMicrosoft Affected 10.0.26200.0 to before 10.0.26200.9711 Fixed in 10.0.26200.9711 Patch available CNA
- Windows 11 version 26H1 VendorMicrosoft Affected 10.0.28000.0 to before 10.0.28000.3231 Fixed in 10.0.28000.3231 Patch available CNA
- Windows 11 Version 26H2 VendorMicrosoft Affected 10.0.26300.0 to before 10.0.26300.9711 Fixed in 10.0.26300.9711 Patch available CNA
- Windows Server 2022 VendorMicrosoft Affected 10.0.20348.0 to before 10.0.20348.5761 Fixed in 10.0.20348.5761 Patch available CNA
- Windows Server 2025 VendorMicrosoft Affected 10.0.26100.0 to before 10.0.26100.33650 Fixed in 10.0.26100.33650 Patch available CNA
- Windows Server 2025 (Server Core installation) VendorMicrosoft Affected 10.0.26100.0 to before 10.0.26100.33650 Fixed in 10.0.26100.33650 Patch available CNA
CPE configurations NVD · 10
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:microsoft:windows_11_24h2:*:*:*:*:*:*:arm64:* | before 10.0.26100.9711 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_11_24h2:*:*:*:*:*:*:x64:* | before 10.0.26100.9711 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_11_25h2:*:*:*:*:*:*:arm64:* | before 10.0.26200.9711 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_11_25h2:*:*:*:*:*:*:x64:* | before 10.0.26200.9711 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_11_26h1:*:*:*:*:*:*:arm64:* | before 10.0.28000.3231 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_11_26h1:*:*:*:*:*:*:x64:* | before 10.0.28000.3231 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_11_26h2:*:*:*:*:*:*:arm64:* | before 10.0.26300.9711 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_11_26h2:*:*:*:*:*:*:x64:* | before 10.0.26300.9711 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_server_2022:*:*:*:*:*:*:*:* | before 10.0.20348.5761 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_server_2025:*:*:*:*:*:*:x64:* | before 10.0.26100.33650 | Vulnerable | Microsoft |
- cpe:2.3:o:microsoft:windows_11_24h2:*:*:*:*:*:*:arm64:* Versions before 10.0.26100.9711 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_11_24h2:*:*:*:*:*:*:x64:* Versions before 10.0.26100.9711 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_11_25h2:*:*:*:*:*:*:arm64:* Versions before 10.0.26200.9711 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_11_25h2:*:*:*:*:*:*:x64:* Versions before 10.0.26200.9711 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_11_26h1:*:*:*:*:*:*:arm64:* Versions before 10.0.28000.3231 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_11_26h1:*:*:*:*:*:*:x64:* Versions before 10.0.28000.3231 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_11_26h2:*:*:*:*:*:*:arm64:* Versions before 10.0.26300.9711 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_11_26h2:*:*:*:*:*:*:x64:* Versions before 10.0.26300.9711 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_server_2022:*:*:*:*:*:*:*:* Versions before 10.0.20348.5761 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_server_2025:*:*:*:*:*:*:x64:* Versions before 10.0.26100.33650 Vulnerable ·Microsoft
Remediation
Install the fixed builds for each product: Windows 11 Version 24H2 10.0.26100.9711, Windows 11 Version 25H2 10.0.26200.9711, Windows 11 version 26H1 10.0.28000.3231, Windows 11 Version 26H2 10.0.26300.9711, Windows Server 2022 10.0.20348.5761, and Windows Server 2025 including the Server Core installation 10.0.26100.33650.
Written with Claude Haiku 5.5 from the sources below · 2026-10-28
- Fix · CNA Windows 11 Version 24H2 (Microsoft) Fixed in 10.0.26100.9711
- Fix · CNA Windows 11 Version 25H2 (Microsoft) Fixed in 10.0.26200.9711
- Fix · CNA Windows 11 version 26H1 (Microsoft) Fixed in 10.0.28000.3231
- Fix · CNA Windows 11 Version 26H2 (Microsoft) Fixed in 10.0.26300.9711
- Fix · CNA Windows Server 2022 (Microsoft) Fixed in 10.0.20348.5761
- Fix · CNA Windows Server 2025 (Microsoft) Fixed in 10.0.26100.33650
- Fix · CNA Windows Server 2025 (Server Core installation) (Microsoft) Fixed in 10.0.26100.33650
Timeline
- 2026-10-13 Threatist record created from CVE-2026-97790
- 2026-10-13 Alias added: GHSA-hg3m-hc8g-63v7
More Microsoft Windows 11 24h2 vulnerabilities
- TI-2026-26194 Windows Internet Key Exchange (IKE) Service Extensions Remote Code Execution Vulnerability KEVCVSS 3.1CRITICAL 9.8
- TI-2026-73128 Windows Shell Security Feature Bypass Vulnerability KEVCVSS 3.1HIGH 8.8
- TI-2026-17367 MSHTML Framework Security Feature Bypass Vulnerability KEVCVSS 3.1HIGH 8.8
- TI-2026-17364 Windows Shell Security Feature Bypass Vulnerability KEVCVSS 3.1HIGH 8.8
- TI-2025-24062 Windows SMB Client Elevation of Privilege Vulnerability KEVCVSS 3.1HIGH 8.8
- TI-2025-24042 Internet Shortcut Files Remote Code Execution Vulnerability KEVCVSS 3.1HIGH 8.8
Sources
- CVE-2026-97790 · CVE Program
- CVE-2026-97790 · NVD
- FIRST EPSS
- GHSA-hg3m-hc8g-63v7 · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences