Vulnerable component: Microsoft Exchange Server
CVSSv3 score: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:H/RL:O/RC:C
CWE-ID: CWE-20 - Improper Input Validation
The vulnerability allows a remote attacker to execute arbitrary code on the system.
The vulnerability exists due to insufficient validation of user-supplied input. A remote attacker can send specially crafted data to the Exchange server and execute arbitrary code on the system.
Note, this vulnerability is being actively exploited in the wild.