# CVE-2016-3320: Secure Boot Security Feature Bypass Vulnerability

CVE-2016-3320 is fixed in 11 products on 1 platform, first by KB3172729, released August 9, 2016. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2016-3320
- Priority: Routine
- CVSS: 6.6 (Important)
- EPSS: 0.0487
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Vendor exploitability assessment: Exploitation Less Likely
- Published: Aug 9, 2016
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2016-3320

## Description

<p>A security feature bypass vulnerability exists when Windows Secure Boot improperly loads a boot manager that is affected by the vulnerability. An attacker who successfully exploited this vulnerability could disable code integrity checks, allowing test-signed executables and drivers to be loaded onto a target device. Furthermore, the attacker could bypass Secure Boot Integrity Validation for BitLocker and Device Encryption security features.</p> <p>To exploit the vulnerability, an attacker who has gained administrative privileges or who has physical access to a target device could install an affected boot manager and then install a policy affected by the vulnerability onto a target device.</p> <p>The security update addresses the vulnerability by blacklisting affected boot managers.</p>

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Microsoft | Windows 10 Version 1511 for 32-bit Systems |  | [KB3172729](https://patchblox.com/security/data/fix/microsoft/kb3172729.md) | Aug 9, 2016 |
| Microsoft | Windows 10 Version 1511 for x64-based Systems |  | [KB3172729](https://patchblox.com/security/data/fix/microsoft/kb3172729.md) | Aug 9, 2016 |
| Microsoft | Windows 10 for 32-bit Systems |  | [KB3172729](https://patchblox.com/security/data/fix/microsoft/kb3172729.md) | Aug 9, 2016 |
| Microsoft | Windows 10 for x64-based Systems |  | [KB3172729](https://patchblox.com/security/data/fix/microsoft/kb3172729.md) | Aug 9, 2016 |
| Microsoft | Windows 8.1 for 32-bit systems |  | [KB3172729](https://patchblox.com/security/data/fix/microsoft/kb3172729.md) | Aug 9, 2016 |
| Microsoft | Windows 8.1 for x64-based systems |  | [KB3172729](https://patchblox.com/security/data/fix/microsoft/kb3172729.md) | Aug 9, 2016 |
| Microsoft | Windows RT 8.1 |  | [KB3172729](https://patchblox.com/security/data/fix/microsoft/kb3172729.md) | Aug 9, 2016 |
| Microsoft | Windows Server 2012 |  | [KB3172729](https://patchblox.com/security/data/fix/microsoft/kb3172729.md) | Aug 9, 2016 |
| Microsoft | Windows Server 2012 (Server Core installation) |  | [KB3172729](https://patchblox.com/security/data/fix/microsoft/kb3172729.md) | Aug 9, 2016 |
| Microsoft | Windows Server 2012 R2 |  | [KB3172729](https://patchblox.com/security/data/fix/microsoft/kb3172729.md) | Aug 9, 2016 |
| Microsoft | Windows Server 2012 R2 (Server Core installation) |  | [KB3172729](https://patchblox.com/security/data/fix/microsoft/kb3172729.md) | Aug 9, 2016 |

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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