Use-after-free in Windows DHCP Client allows code execution
Key facts
- Attack vector
- Adjacent network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Code execution
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Microsoft. Impact type from Microsoft.
Summary
Windows Server 2012 from 6.2.9200.0 before 6.2.9200.26434, Windows Server 2012 R2 from 6.3.9600.0 before 6.3.9600.23470, and other listed Windows Server releases contain a use-after-free flaw (CWE-416) in the Windows DHCP Client. An unauthorized attacker on an adjacent network can execute code. Microsoft rates exploitation as less likely.
Written with Claude Haiku 5.5 from the sources below · 2026-10-29
Description from the CNA
Use after free in Windows DHCP Client allows an unauthorized attacker to execute code over an adjacent network.
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 Server 2012 | 6.2.9200.0 to before 6.2.9200.26434 | 6.2.9200.26434 | Patch available | CNA |
| Microsoft | Windows Server 2012 (Server Core installation) | 6.2.9200.0 to before 6.2.9200.26434 | 6.2.9200.26434 | Patch available | CNA |
| Microsoft | Windows Server 2012 R2 | 6.3.9600.0 to before 6.3.9600.23470 | 6.3.9600.23470 | Patch available | CNA |
| Microsoft | Windows Server 2012 R2 (Server Core installation) | 6.3.9600.0 to before 6.3.9600.23470 | 6.3.9600.23470 | Patch available | CNA |
| Microsoft | Windows Server 2016 | 10.0.14393.0 to before 10.0.14393.9612 | 10.0.14393.9612 | Patch available | CNA |
| Microsoft | Windows Server 2016 (Server Core installation) | 10.0.14393.0 to before 10.0.14393.9612 | 10.0.14393.9612 | Patch available | CNA |
| Microsoft | Windows Server 2019 | 10.0.17763.0 to before 10.0.17763.9376 | 10.0.17763.9376 | Patch available | CNA |
| Microsoft | Windows Server 2019 (Server Core installation) | 10.0.17763.0 to before 10.0.17763.9376 | 10.0.17763.9376 | 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 Server 2012 VendorMicrosoft Affected 6.2.9200.0 to before 6.2.9200.26434 Fixed in 6.2.9200.26434 Patch available CNA
- Windows Server 2012 (Server Core installation) VendorMicrosoft Affected 6.2.9200.0 to before 6.2.9200.26434 Fixed in 6.2.9200.26434 Patch available CNA
- Windows Server 2012 R2 VendorMicrosoft Affected 6.3.9600.0 to before 6.3.9600.23470 Fixed in 6.3.9600.23470 Patch available CNA
- Windows Server 2012 R2 (Server Core installation) VendorMicrosoft Affected 6.3.9600.0 to before 6.3.9600.23470 Fixed in 6.3.9600.23470 Patch available CNA
- Windows Server 2016 VendorMicrosoft Affected 10.0.14393.0 to before 10.0.14393.9612 Fixed in 10.0.14393.9612 Patch available CNA
- Windows Server 2016 (Server Core installation) VendorMicrosoft Affected 10.0.14393.0 to before 10.0.14393.9612 Fixed in 10.0.14393.9612 Patch available CNA
- Windows Server 2019 VendorMicrosoft Affected 10.0.17763.0 to before 10.0.17763.9376 Fixed in 10.0.17763.9376 Patch available CNA
- Windows Server 2019 (Server Core installation) VendorMicrosoft Affected 10.0.17763.0 to before 10.0.17763.9376 Fixed in 10.0.17763.9376 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 · 6
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:microsoft:windows_server_2012:-:*:*:*:*:*:*:* | not specified by NVD | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_server_2012:r2:*:*:*:*:*:*:* | r2 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_server_2016:*:*:*:*:*:*:x64:* | before 10.0.14393.9612 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_server_2019:*:*:*:*:*:*:x64:* | before 10.0.17763.9376 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_server_2022:*:*:*:*:*:*:x64:* | 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_server_2012:-:*:*:*:*:*:*:* Versions not specified by NVD Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_server_2012:r2:*:*:*:*:*:*:* Versions r2 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_server_2016:*:*:*:*:*:*:x64:* Versions before 10.0.14393.9612 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_server_2019:*:*:*:*:*:*:x64:* Versions before 10.0.17763.9376 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_server_2022:*:*:*:*:*:*:x64:* 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: Windows Server 2012 (including Server Core) 6.2.9200.26434 with KB5126835; Windows Server 2012 R2 (including Server Core) 6.3.9600.23470 with KB5126836; Windows Server 2016 (including Server Core) 10.0.14393.9612 with KB5126868; Windows Server 2019 (including Server Core) 10.0.17763.9376 with KB5126651; Windows Server 2022 (including Server Core) 10.0.20348.5761 with KB5126655; Windows Server 2025 (including Server Core) 10.0.26100.33650 with KB5126646.
Written with Claude Haiku 5.5 from the sources below · 2026-10-29
Microsoft 6 updates
- Security Update
- Microsoft .NET Framework 3.5 AND 4.6.2/4.7/4.7.1/4.7.2 2.0.50727.8987 AND 3.0.30729.8982 AND 4.7.4150.0
- Windows 10 Version 1607 for 32-bit Systems 10.0.14393.9612
- Windows 10 Version 1607 for x64-based Systems 10.0.14393.9612
- Windows Server 2016 10.0.14393.9612
- Windows Server 2016 (Server Core installation) 10.0.14393.9612
- Security Update
- Windows Server 2012 R2 6.3.9600.23470
- Windows Server 2012 R2 (Server Core installation) 6.3.9600.23470
- Security Update
- Windows Server 2012 6.2.9200.26434
- Windows Server 2012 (Server Core installation) 6.2.9200.26434
Show 3 more Microsoft updates
- Security Update
- Windows Server 2022 10.0.20348.5761
- Windows Server 2022 (Server Core installation) 10.0.20348.5761
- Security Update
- Windows 10 Version 1809 for 32-bit Systems 10.0.17763.9376
- Windows 10 Version 1809 for x64-based Systems 10.0.17763.9376
- Windows Server 2019 10.0.17763.9376
- Windows Server 2019 (Server Core installation) 10.0.17763.9376
- Security Update
- Windows Server 2025 10.0.26100.33650
- Windows Server 2025 (Server Core installation) 10.0.26100.33650
Vendor assessments
Microsoft
Microsoft's page for this CVE →
- Impact
- Remote Code Execution
- Exploited
- No
- Publicly disclosed
- No
- Exploitability
- Exploitation Less Likely
Timeline
- 2026-10-13 Threatist record created from CVE-2026-70250
- 2026-10-13 Alias added: GHSA-mfg7-c74w-738f
- 2026-10-13 CISA SSVC decision points changed
- 2026-10-14 Priority changed: MEDIUM → LOW
- 2026-10-14 Priority changed: LOW → MEDIUM
- 2026-10-29 Fix available: KB5126646, KB5126651, KB5126655 +3 · Microsoft
References
More Microsoft Windows Server 2012 vulnerabilities
- TI-2025-36863 Windows Server Update Service (WSUS) Remote Code Execution Vulnerability KEVCVSS 3.1CRITICAL 9.8
- TI-2020-01431 Netlogon Elevation of Privilege Vulnerability KEVCVSS 3.1CRITICAL 10.0
- TI-2020-01310 Improper input validation in Microsoft Windows Server KEVCVSS 3.1CRITICAL 10.0
- TI-2017-06077 Microsoft Windows XP SP3, Windows XP x64 XP2, Windows Server 2003 SP2, Windows Vista… KEVCVSS 3.1CRITICAL 9.8
- TI-2015-01465 HTTP.sys in Microsoft Windows 7 SP1, Windows Server 2008 R2 SP1, Windows 8, Windows 8.1… KEVCVSS 3.1CRITICAL 9.8
- TI-2020-01009 Improper input validation in Microsoft Windows Server KEVCVSS 3.1CRITICAL 9.0
Sources
- CVE-2026-70250 · CVE Program
- CVE-2026-70250 · NVD
- FIRST EPSS
- GHSA-mfg7-c74w-738f · GitHub Advisory Database · CC BY 4.0
- CVE-2026-70250 · Microsoft Security Update Guide
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences