This security update resolves a remote code execution vulnerability that exists in Microsoft Outlook if the software does not correctly handle objects in memory. It also resolves a denial of service vulnerability that exists in Microsoft Exchange Server if the software does not correctly handle objects in memory. To learn more about these vulnerabilities, see Microsoft Common Vulnerabilities and Exposures CVE-2020-16947 and Microsoft Common Vulnerabilities and Exposures CVE-2020-16949.
Note To apply this security update, you must have the release version of Outlook 2016 installed on the computer.
Be aware that the update in the Microsoft Download Center applies to the Microsoft Installer (.msi)-based edition of Office 2016. It doesn't apply to the Office 2016 Click-to-Run editions, such as Microsoft Office 365 Home (see What version of Office am I using?).
Improvements and fixes
- Fixes an issue that causes Outlook to intermittently crash when users interact with calendar items.
- Fixes an issue to correctly block users from being able to forward multiple selected messages that have the "Do Not Forward" policy applied.
- Fixes an issue in which the LegacyExchangeDN value for an email sender is preserved and displayed in the From field after a draft of the email is moved from a mailbox that has assistant permissions to the manager's mailbox.
- Fixes an issue that causes the computers of some users to fail when they connect through MAPI/HTTP.
How to get and install the update
Method 1: Microsoft Update
This update is available from Microsoft Update. When you turn on automatic updating, this update will be downloaded and installed automatically. For more information about how to get security updates automatically, see Windows Update: FAQ.
Method 2: Microsoft Update Catalog
To get the standalone package for this update, go to the Microsoft Update Catalog website.
Method 3: Microsoft Download Center
You can get the standalone update package through the Microsoft Download Center. Follow the installation instructions on the download page to install the update.
Security update deployment information
For deployment information about this update, see security update deployment information: October 13, 2020.
Security update replacement information
This security update replaces previously released security update 4484475.
File hash information
|File name||SHA1 hash||SHA256 hash|
The English (United States) version of this software update installs files that have the attributes that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). The dates and times for these files on your local computer are displayed in your local time together with your current daylight saving time (DST) bias. Additionally, the dates and times may change when you perform certain operations on the files.