# CVE-2016-3227: Windows DNS Server Use After Free Vulnerability

CVE-2016-3227 is fixed in 4 products on 1 platform, first by KB3161951, released June 14, 2016. It is not reported as exploited. Patch Radar priority: Urgent.

- Web page: https://patchblox.com/security/cve/CVE-2016-3227
- Priority: Urgent
- CVSS: n/a (Critical)
- EPSS: 0.2546
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Vendor exploitability assessment: Exploitation Less Likely
- Published: Jun 14, 2016
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2016-3227

## Description

<p>A remote code execution vulnerability exists in Windows <a href="undefinedhttps://technet.microsoft.com/en-us/library/security/dn848375.aspx#DNS">Domain Name System (DNS)</a> servers when they fail to properly handle requests. An attacker who successfully exploited the vulnerability could run arbitrary code in the context of the Local System Account. Windows servers that are configured as DNS servers are at risk from this vulnerability.</p> <p>To exploit the vulnerability, an unauthenticated attacker could send malicious requests to a Windows DNS server.</p> <p>The update addresses the vulnerability by modifying how Windows DNS servers handle requests.</p>

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Microsoft | Windows Server 2012 |  | [KB3161951](https://patchblox.com/security/data/fix/microsoft/kb3161951.md) | Jun 14, 2016 |
| Microsoft | Windows Server 2012 (Server Core installation) |  | [KB3161951](https://patchblox.com/security/data/fix/microsoft/kb3161951.md) | Jun 14, 2016 |
| Microsoft | Windows Server 2012 R2 |  | [KB3161951](https://patchblox.com/security/data/fix/microsoft/kb3161951.md) | Jun 14, 2016 |
| Microsoft | Windows Server 2012 R2 (Server Core installation) |  | [KB3161951](https://patchblox.com/security/data/fix/microsoft/kb3161951.md) | Jun 14, 2016 |

---

Data as of 2026-11-07T06:34:28Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo