The issue was discovered in the wild by ISS xForce.
Vulnerable component: Microsoft XML Core Services
CVSSv3 score: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H/E:F/RL:O/RC:C
CWE-ID: CWE-119 - Improper Restriction of Operations within the Bounds of a Memory Buffer
The vulnerability allows a remote attacker to execute arbitrary code on the target system.
The vulnerability exists due to an error in XMLHTTP ActiveX control within Microsoft XML Core Services. A remote unauthenticated attacker can trick the victim to open a specially crafted web page and execute arbitrary code on the target system with privileges of the current user.
Successful exploitation of this vulnerability may allow an attacker to compromise vulnerable system.
Note: this vulnerability is being actively exploited.