CVE-2026-109463: Windows DNS Remote Code Execution Vulnerability
CVE-2026-109463 is a remote code execution vulnerability in Windows DNS, rated Important by Microsoft, with a CVSS 3.1 base score of 8.8 (High). An attacker can exploit it remotely over the network, without any privileges and only if a user takes an action. Microsoft has not reported exploitation in the wild and rates exploitation as less likely. Microsoft released the fix on 10 November 2026 in the November 2026 Patch Tuesday, delivered through 10 security updates (KB5126835, KB5126836, KB5126868, KB5126651 and more). It affects 32 products in 2 product families (ESU, Windows).
Key facts
- CVE ID
- CVE-2026-109463
- Severity
- High CVSS 8.8
- Microsoft severity
- Important
- Impact
- Remote Code Execution
- Exploited in the wild
- No
- Publicly disclosed
- No
- Exploitation likelihood
- Less Likely
- CISA KEV
- Not listed
- Released
- Last updated
- Patch Tuesday
- November 2026 Patch Tuesday
- Product families
- ESU, Windows
CVSS score and vector
Microsoft scores CVE-2026-109463 at 8.8 (temporal 7.7) using CVSS 3.1. Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
| Metric | Value |
|---|---|
| Attack vector | Network |
| Attack complexity | Low |
| Privileges required | None |
| User interaction | Required |
| Scope | Unchanged |
| Confidentiality impact | High |
| Integrity impact | High |
| Availability impact | High |
| Exploit code maturity | Unproven |
| Remediation level | Official fix |
| Report confidence | Confirmed |
Description
Deserialization of untrusted data in Windows DNS allows an unauthorized attacker to execute code over a network.
Affected products (32)
ESU
| Product | Security update | Type | Fixed build | Restart |
|---|---|---|---|---|
| Windows Server 2012 | KB5126835 | Security Update | 6.2.9200.26434 | Yes |
| Windows Server 2012 (Server Core installation) | KB5126835 | Security Update | 6.2.9200.26434 | Yes |
| Windows Server 2012 R2 | KB5126836 | Security Update | 6.3.9600.23470 | Yes |
| Windows Server 2012 R2 (Server Core installation) | KB5126836 | Security Update | 6.3.9600.23470 | Yes |
| Windows 10 Version 1607 for 32-bit Systems | KB5126868 | Security Update | 10.0.14393.9612 | Yes |
| Windows 10 Version 1607 for x64-based Systems | KB5126868 | Security Update | 10.0.14393.9612 | Yes |
| Windows Server 2016 | KB5126868 | Security Update | 10.0.14393.9612 | Yes |
| Windows Server 2016 (Server Core installation) | KB5126868 | Security Update | 10.0.14393.9612 | Yes |
| Windows 10 Version 22H2 for 32-bit Systems | ||||
| Windows 10 Version 22H2 for ARM64-based Systems | ||||
| Windows 10 Version 22H2 for x64-based Systems |
Windows
| Product | Security update | Type | Fixed build | Restart |
|---|---|---|---|---|
| Windows 10 Version 1809 for 32-bit Systems | KB5126651 | Security Update | 10.0.17763.9376 | Yes |
| Windows 10 Version 1809 for x64-based Systems | KB5126651 | Security Update | 10.0.17763.9376 | Yes |
| Windows Server 2019 | KB5126651 | Security Update | 10.0.17763.9376 | Yes |
| Windows Server 2019 (Server Core installation) | KB5126651 | Security Update | 10.0.17763.9376 | Yes |
| Windows 10 Version 21H2 for 32-bit Systems | KB5126657 | Security Update | 10.0.19044.7807 | Yes |
| Windows 10 Version 21H2 for ARM64-based Systems | KB5126657 | Security Update | 10.0.19044.7807 | Yes |
| Windows 10 Version 21H2 for x64-based Systems | KB5126657 | Security Update | 10.0.19044.7807 | Yes |
| Windows Server 2022 | KB5126655 | Security Update | 10.0.20348.5761 | Yes |
| Windows Server 2022 (Server Core installation) | KB5126655 | Security Update | 10.0.20348.5761 | Yes |
| Windows 11 Version 23H2 for ARM64-based Systems | KB5126653 | Security Update | 10.0.22631.7652 | Yes |
| Windows 11 Version 23H2 for x64-based Systems | KB5126653 | Security Update | 10.0.22631.7652 | Yes |
| Windows 11 Version 24H2 for ARM64-based Systems | KB5127648 | Security Update | 10.0.26100.9711 | Yes |
| Windows 11 Version 24H2 for x64-based Systems | KB5127648 | Security Update | 10.0.26100.9711 | Yes |
| Windows 11 Version 25H2 for ARM64-based Systems | ||||
| Windows 11 Version 25H2 for x64-based Systems | ||||
| Windows 11 Version 26H2 for ARM64-based Systems | ||||
| Windows 11 Version 26H2 for x64-based Systems | ||||
| Windows Server 2025 | KB5126646 | Security Update | 10.0.26100.33650 | Yes |
| Windows Server 2025 (Server Core installation) | KB5126646 | Security Update | 10.0.26100.33650 | Yes |
| Windows 11 Version 26H1 for ARM64-based Systems | KB5127646 | Security Update | 10.0.28000.3231 | Yes |
| Windows 11 version 26H1 for x64-based Systems | KB5127646 | Security Update | 10.0.28000.3231 | Yes |
Security updates (10)
Acknowledgments
Revision history
| Version | Date | Description |
|---|---|---|
| 1.0 | Information published. |