This update rollup is a security update that resolves vulnerabilities in Microsoft Exchange. To learn more about these vulnerabilities, see the following Common Vulnerabilities and Exposures (CVE):
Known issues in this security update
When you try to manually install this security update by double-clicking the update file (.msp) to run it in Normal mode (that is, not as an administrator), some files are not correctly updated.
When this issue occurs, you don’t receive an error message or any indication that the security update was not correctly installed. However, Outlook Web Access (OWA) and the Exchange Control Panel (ECP) may stop working.
This issue occurs on servers that are using User Account Control (UAC). The issue occurs because the security update doesn’t correctly stop certain Exchange-related services.
To avoid this issue, follow these steps to manually install this security update:
- Select Start, and type cmd.
- In the results, right-click Command Prompt, and then select Run as administrator.
- If the User Account Control dialog box appears, confirm that the default action is the action that you want, and then select Continue.
- Type the full path of the .msp file, and then press Enter.
This issue does not occur if you install the update through Microsoft Update.
Exchange services may remain in a disabled state after you install this security update. This condition does not indicate that the update is not installed correctly. This condition may occur if the service control scripts experience a problem when they try to return Exchange services to their usual state.
To fix this issue, use Services Manager to restore the startup type to Automatic, and then start the affected Exchange services manually. To avoid this issue, run the security update at an elevated command prompt. For more information about how to open an elevated Command Prompt window, see Start a Command Prompt as an Administrator.
When you block third-party cookies in a web browser, you may be continually prompted to trust a particular add-in even though you keep selecting the option to trust it. This issue occurs also in privacy window modes (such as InPrivate mode in Microsoft Edge). This issue occurs because browser restrictions prevent the response from being recorded. To record the response and enable the add-in, you must enable third-party cookies for the domain that's hosting OWA or Office Online Server in the browser settings. To enable this setting, refer to the specific support documentation for the browser.
How to get and install the update
Method 1: Microsoft Update
This update is available through Windows Update. When you turn on automatic updating, this update will be downloaded and installed automatically. For more information about how to turn on automatic updating, 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.
Security update deployment information
For deployment information about this update, see security update deployment information: December 8, 2020.
Security update replacement information
This security update replaces the following previously released updates:
File hash information
|Update name||File name||SHA1 hash||SHA256 hash|
|Exchange Server 2013 Cumulative Update 23 ||Exchange2013-KB4593466-x64-en.msp||CA51F7116309402D53821977992A6B407AE96822||2912A721CAD456D20D24A68C84D56B48218A65F0960FEEE12BB66814C41E1871|
Exchange server file information
The English (United States) version of this update installs files that have the attributes that are listed in the following tables. 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.