# CVE-2021-27085: Internet Explorer Remote Code Execution Vulnerability

CVE-2021-27085 is fixed in 16 products on 1 platform, first by KB5000809, released March 9, 2021. It is being exploited: CISA added it to the Known Exploited Vulnerabilities catalog on November 3, 2021. Patch Radar priority: Patch now.

- Web page: https://patchblox.com/security/cve/CVE-2021-27085
- Priority: Patch now
- CVSS: 8.8 (Important)
- EPSS: 0.0545
- CISA KEV: listed Nov 3, 2021, federal due date Nov 17, 2021
- Exploited (vendor report): yes
- Publicly disclosed: no
- Vendor exploitability assessment: Exploitation Detected
- Published: Mar 12, 2021
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-27085

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Microsoft | Internet Explorer 11 on Windows 10 Version 1803 for 32-bit Systems | 17134.2087 | [KB5000809](https://patchblox.com/security/data/fix/microsoft/kb5000809.md) | Mar 9, 2021 |
| Microsoft | Internet Explorer 11 on Windows 10 Version 1803 for ARM64-based Systems | 17134.2087 | [KB5000809](https://patchblox.com/security/data/fix/microsoft/kb5000809.md) | Mar 9, 2021 |
| Microsoft | Internet Explorer 11 on Windows 10 Version 1803 for x64-based Systems | 17134.2087 | [KB5000809](https://patchblox.com/security/data/fix/microsoft/kb5000809.md) | Mar 9, 2021 |
| Microsoft | Internet Explorer 11 on Windows 10 Version 1809 for 32-bit Systems | 17763.1817 | [KB5000822](https://patchblox.com/security/data/fix/microsoft/kb5000822.md) | Mar 9, 2021 |
| Microsoft | Internet Explorer 11 on Windows 10 Version 1809 for ARM64-based Systems | 17763.1817 | [KB5000822](https://patchblox.com/security/data/fix/microsoft/kb5000822.md) | Mar 9, 2021 |
| Microsoft | Internet Explorer 11 on Windows 10 Version 1809 for x64-based Systems | 17763.1817 | [KB5000822](https://patchblox.com/security/data/fix/microsoft/kb5000822.md) | Mar 9, 2021 |
| Microsoft | Internet Explorer 11 on Windows 10 Version 1909 for 32-bit Systems | 18363.1440 | [KB5000808](https://patchblox.com/security/data/fix/microsoft/kb5000808.md) | Mar 9, 2021 |
| Microsoft | Internet Explorer 11 on Windows 10 Version 1909 for ARM64-based Systems | 18363.1440 | [KB5000808](https://patchblox.com/security/data/fix/microsoft/kb5000808.md) | Mar 9, 2021 |
| Microsoft | Internet Explorer 11 on Windows 10 Version 1909 for x64-based Systems | 18363.1440 | [KB5000808](https://patchblox.com/security/data/fix/microsoft/kb5000808.md) | Mar 9, 2021 |
| Microsoft | Internet Explorer 11 on Windows 10 Version 2004 for 32-bit Systems |  | [KB5000802](https://patchblox.com/security/data/fix/microsoft/kb5000802.md) | Mar 9, 2021 |
| Microsoft | Internet Explorer 11 on Windows 10 Version 2004 for ARM64-based Systems |  | [KB5000802](https://patchblox.com/security/data/fix/microsoft/kb5000802.md) | Mar 9, 2021 |
| Microsoft | Internet Explorer 11 on Windows 10 Version 2004 for x64-based Systems |  | [KB5000802](https://patchblox.com/security/data/fix/microsoft/kb5000802.md) | Mar 9, 2021 |
| Microsoft | Internet Explorer 11 on Windows 10 Version 20H2 for 32-bit Systems |  | [KB5000802](https://patchblox.com/security/data/fix/microsoft/kb5000802.md) | Mar 9, 2021 |
| Microsoft | Internet Explorer 11 on Windows 10 Version 20H2 for ARM64-based Systems |  | [KB5000802](https://patchblox.com/security/data/fix/microsoft/kb5000802.md) | Mar 9, 2021 |
| Microsoft | Internet Explorer 11 on Windows 10 Version 20H2 for x64-based Systems |  | [KB5000802](https://patchblox.com/security/data/fix/microsoft/kb5000802.md) | Mar 9, 2021 |
| Microsoft | Internet Explorer 11 on Windows Server 2019 | 17763.1817 | [KB5000822](https://patchblox.com/security/data/fix/microsoft/kb5000822.md) | Mar 9, 2021 |

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Data as of 2026-11-09T19:38:12Z 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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