# CVE-2021-1638: Windows Bluetooth Security Feature Bypass Vulnerability

CVE-2021-1638 is fixed in 19 products on 1 platform, first by KB4598245, released January 12, 2021. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2021-1638
- Priority: High
- CVSS: 7.7 (Important)
- EPSS: 0.0123
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Vendor exploitability assessment: Exploitation Less Likely
- Published: Jan 12, 2021
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-1638

## Description

<p>Microsoft is aware of the "Impersonation in the Passkey Entry Protocol" vulnerability. For more information regarding the vulnerability, please see this <a href="https://www.bluetooth.com/learn-about-bluetooth/key-attributes/bluetooth-security/passkey-impersonation/">statement</a> from the Bluetooth SIG.</p> <p>To address the vulnerability, Microsoft has released a software update that will fail attempts to pair if the remote device exchanges a public key with the same X coordinate as the locally exchanged public key</p>

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Microsoft | Windows 10 Version 1803 for 32-bit Systems | 17134.1967 | [KB4598245](https://patchblox.com/security/data/fix/microsoft/kb4598245.md) | Jan 12, 2021 |
| Microsoft | Windows 10 Version 1803 for ARM64-based Systems | 17134.1967 | [KB4598245](https://patchblox.com/security/data/fix/microsoft/kb4598245.md) | Jan 12, 2021 |
| Microsoft | Windows 10 Version 1803 for x64-based Systems | 17134.1967 | [KB4598245](https://patchblox.com/security/data/fix/microsoft/kb4598245.md) | Jan 12, 2021 |
| Microsoft | Windows 10 Version 1809 for 32-bit Systems | 17763.1697 | [KB4598230](https://patchblox.com/security/data/fix/microsoft/kb4598230.md) | Jan 12, 2021 |
| Microsoft | Windows 10 Version 1809 for ARM64-based Systems | 17763.1697 | [KB4598230](https://patchblox.com/security/data/fix/microsoft/kb4598230.md) | Jan 12, 2021 |
| Microsoft | Windows 10 Version 1809 for x64-based Systems | 17763.1697 | [KB4598230](https://patchblox.com/security/data/fix/microsoft/kb4598230.md) | Jan 12, 2021 |
| Microsoft | Windows 10 Version 1909 for 32-bit Systems | 18363.1316 | [KB4598229](https://patchblox.com/security/data/fix/microsoft/kb4598229.md) | Jan 12, 2021 |
| Microsoft | Windows 10 Version 1909 for ARM64-based Systems | 18363.1316 | [KB4598229](https://patchblox.com/security/data/fix/microsoft/kb4598229.md) | Jan 12, 2021 |
| Microsoft | Windows 10 Version 1909 for x64-based Systems | 18363.1316 | [KB4598229](https://patchblox.com/security/data/fix/microsoft/kb4598229.md) | Jan 12, 2021 |
| Microsoft | Windows 10 Version 2004 for 32-bit Systems |  | [KB4598242](https://patchblox.com/security/data/fix/microsoft/kb4598242.md) | Jan 12, 2021 |
| Microsoft | Windows 10 Version 2004 for ARM64-based Systems |  | [KB4598242](https://patchblox.com/security/data/fix/microsoft/kb4598242.md) | Jan 12, 2021 |
| Microsoft | Windows 10 Version 2004 for x64-based Systems |  | [KB4598242](https://patchblox.com/security/data/fix/microsoft/kb4598242.md) | Jan 12, 2021 |
| Microsoft | Windows 10 Version 20H2 for 32-bit Systems |  | [KB4598242](https://patchblox.com/security/data/fix/microsoft/kb4598242.md) | Jan 12, 2021 |
| Microsoft | Windows 10 Version 20H2 for ARM64-based Systems |  | [KB4598242](https://patchblox.com/security/data/fix/microsoft/kb4598242.md) | Jan 12, 2021 |
| Microsoft | Windows Server 2019 | 17763.1697 | [KB4598230](https://patchblox.com/security/data/fix/microsoft/kb4598230.md) | Jan 12, 2021 |
| Microsoft | Windows Server 2019 (Server Core installation) | 17763.1697 | [KB4598230](https://patchblox.com/security/data/fix/microsoft/kb4598230.md) | Jan 12, 2021 |
| Microsoft | Windows Server, version 1909 (Server Core installation) | 18363.1316 | [KB4598229](https://patchblox.com/security/data/fix/microsoft/kb4598229.md) | Jan 12, 2021 |
| Microsoft | Windows Server, version 2004 (Server Core installation) |  | [KB4598242](https://patchblox.com/security/data/fix/microsoft/kb4598242.md) | Jan 12, 2021 |
| Microsoft | Windows Server, version 20H2 (Server Core Installation) |  | [KB4598242](https://patchblox.com/security/data/fix/microsoft/kb4598242.md) | Jan 12, 2021 |

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Data as of 2026-11-08T13:06:02Z 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

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