# CVE-2020-16949: Microsoft Outlook Denial of Service Vulnerability

CVE-2020-16949 is fixed in 7 products on 1 platform, first by KB4486663, released October 13, 2020. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2020-16949
- Priority: Routine
- CVSS: 4.7 (Moderate)
- EPSS: 0.0297
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Vendor exploitability assessment: Exploitation Less Likely
- Published: Oct 13, 2020
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2020-16949

## Description

<p>A denial of service vulnerability exists in Microsoft Outlook software when the software fails to properly handle objects in memory. An attacker who successfully exploited the vulnerability could cause a remote denial of service against a system.</p> <p>Exploitation of the vulnerability requires that a specially crafted email be sent to a vulnerable Outlook server.</p> <p>The security update addresses the vulnerability by correcting how Microsoft Outlook handles objects in memory.</p>

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Microsoft | Microsoft Outlook 2010 Service Pack 2 (32-bit editions) |  | [KB4486663](https://patchblox.com/security/data/fix/microsoft/kb4486663.md) | Oct 13, 2020 |
| Microsoft | Microsoft Outlook 2010 Service Pack 2 (64-bit editions) |  | [KB4486663](https://patchblox.com/security/data/fix/microsoft/kb4486663.md) | Oct 13, 2020 |
| Microsoft | Microsoft Outlook 2013 RT Service Pack 1 |  | [KB4484524](https://patchblox.com/security/data/fix/microsoft/kb4484524.md) | Oct 13, 2020 |
| Microsoft | Microsoft Outlook 2013 Service Pack 1 (32-bit editions) |  | [KB4484524](https://patchblox.com/security/data/fix/microsoft/kb4484524.md) | Oct 13, 2020 |
| Microsoft | Microsoft Outlook 2013 Service Pack 1 (64-bit editions) |  | [KB4484524](https://patchblox.com/security/data/fix/microsoft/kb4484524.md) | Oct 13, 2020 |
| Microsoft | Microsoft Outlook 2016 (32-bit edition) |  | [KB4486671](https://patchblox.com/security/data/fix/microsoft/kb4486671.md) | Oct 15, 2020 |
| Microsoft | Microsoft Outlook 2016 (64-bit edition) |  | [KB4486671](https://patchblox.com/security/data/fix/microsoft/kb4486671.md) | Oct 15, 2020 |

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Data as of 2026-11-08T06:59:42Z 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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