Microsoft Exchange Server Elevation of Privilege Vulnerability

How could an attacker exploit this vulnerability?
To exploit this vulnerability, an attacker would first have to log on to the system. An attacker could then run a specially crafted application that could exploit the vulnerability and take control of an affected system.
Additionally, an attacker could convince a local user to open a malicious file. The attacker would have to convince the user to click a link, typically by way of an enticement in an email or instant message, and then convince them to open the specially crafted file.

What privileges could be gained by an attacker who successfully exploited the vulnerability?
The attacker would be able to take over the mailboxes of all Exchange users, read emails, download attachments.

Security updates
15.02.1748.039 — https://support.microsoft.com/help/5066367
15.02.1544.036 — https://support.microsoft.com/help/5066368
15.02.2562.029 — https://support.microsoft.com/help/5066366
15.01.2507.061 — https://support.microsoft.com/help/5066369