Windows Backup Engine flaw allows local privilege escalation
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA.
Summary
Windows 10 Version 21H2, Windows 10 Version 22H2, and several Windows 11 versions (23H2, 24H2, 25H2, 26H1, 26H2) are affected. Windows Backup Engine does not correctly resolve equivalent file paths (CWE-41), which lets an authorized local attacker escalate privileges. The attacker needs low privileges and no user interaction, and a successful attack has high impact on confidentiality, integrity and availability.
Written with Claude Haiku 5.5 from the sources below · 2026-10-27
Description from the CNA
Improper resolution of path equivalence in Windows Backup Engine allows an authorized attacker to elevate privileges locally.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
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 10 Version 21H2 | 10.0.19044.0 to before 10.0.19044.7807 | 10.0.19044.7807 | Patch available | CNA |
| Microsoft | Windows 10 Version 22H2 | 10.0.19045.0 to before 10.0.19045.7807 | 10.0.19045.7807 | Patch available | CNA |
| Microsoft | Windows 11 version 23H2 | 10.0.22631.0 to before 10.0.22631.7652 | 10.0.22631.7652 | Patch available | CNA |
| Microsoft | Windows 11 Version 23H2 | 10.0.22631.0 to before 10.0.22631.7652 | 10.0.22631.7652 | Patch available | CNA |
| 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 |
- Windows 10 Version 21H2 VendorMicrosoft Affected 10.0.19044.0 to before 10.0.19044.7807 Fixed in 10.0.19044.7807 Patch available CNA
- Windows 10 Version 22H2 VendorMicrosoft Affected 10.0.19045.0 to before 10.0.19045.7807 Fixed in 10.0.19045.7807 Patch available CNA
- Windows 11 version 23H2 VendorMicrosoft Affected 10.0.22631.0 to before 10.0.22631.7652 Fixed in 10.0.22631.7652 Patch available CNA
- Windows 11 Version 23H2 VendorMicrosoft Affected 10.0.22631.0 to before 10.0.22631.7652 Fixed in 10.0.22631.7652 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
CPE configurations NVD · 16
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:microsoft:windows_10_21h2:*:*:*:*:*:*:arm64:* | before 10.0.19044.7807 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_10_21h2:*:*:*:*:*:*:x64:* | before 10.0.19044.7807 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_10_21h2:*:*:*:*:*:*:x86:* | before 10.0.19044.7807 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_10_22h2:*:*:*:*:*:*:arm64:* | before 10.0.19045.7807 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_10_22h2:*:*:*:*:*:*:x64:* | before 10.0.19045.7807 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_10_22h2:*:*:*:*:*:*:x86:* | before 10.0.19045.7807 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_11_23h2:*:*:*:*:*:*:arm64:* | before 10.0.22631.7652 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_11_23h2:*:*:*:*:*:*:x64:* | before 10.0.22631.7652 | Vulnerable | Microsoft |
| 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_10_21h2:*:*:*:*:*:*:arm64:* Versions before 10.0.19044.7807 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_10_21h2:*:*:*:*:*:*:x64:* Versions before 10.0.19044.7807 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_10_21h2:*:*:*:*:*:*:x86:* Versions before 10.0.19044.7807 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_10_22h2:*:*:*:*:*:*:arm64:* Versions before 10.0.19045.7807 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_10_22h2:*:*:*:*:*:*:x64:* Versions before 10.0.19045.7807 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_10_22h2:*:*:*:*:*:*:x86:* Versions before 10.0.19045.7807 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_11_23h2:*:*:*:*:*:*:arm64:* Versions before 10.0.22631.7652 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_11_23h2:*:*:*:*:*:*:x64:* Versions before 10.0.22631.7652 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
Show 6 more CPE
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| 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_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
Remediation
Install the fixed builds: 10.0.19044.7807 for Windows 10 Version 21H2, 10.0.19045.7807 for Windows 10 Version 22H2, 10.0.22631.7652 for Windows 11 Version 23H2, 10.0.26100.9711 for Windows 11 Version 24H2, 10.0.26200.9711 for Windows 11 Version 25H2, 10.0.28000.3231 for Windows 11 Version 26H1, and 10.0.26300.9711 for Windows 11 Version 26H2.
Written with Claude Haiku 5.5 from the sources below · 2026-10-27
- Fix · CNA Windows 10 Version 21H2 (Microsoft) Fixed in 10.0.19044.7807
- Fix · CNA Windows 10 Version 22H2 (Microsoft) Fixed in 10.0.19045.7807
- Fix · CNA Windows 11 version 23H2 (Microsoft) Fixed in 10.0.22631.7652
- Fix · CNA Windows 11 Version 23H2 (Microsoft) Fixed in 10.0.22631.7652
- 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
Timeline
- 2026-10-13 Threatist record created from CVE-2026-70184
- 2026-10-13 Alias added: GHSA-w6gw-x9rc-48qx
- 2026-10-13 CISA SSVC decision points changed
- 2026-10-14 Priority changed: MEDIUM → LOW
- 2026-10-16 Fix available: Microsoft/Windows 10 Version [email protected] · CNA
References
More Microsoft Windows 10 21h2 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-2026-70184 · CVE Program
- CVE-2026-70184 · NVD
- FIRST EPSS
- GHSA-w6gw-x9rc-48qx · 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