Vulnerable component: Microsoft SharePoint Server
CVSSv3 score: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N/E:F/RL:O/RC:C
CWE-ID: CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
The vulnerability allows a remote attacker to obtain elevated privileges on the target system.
The weakness exists due to an error related to the way HTML strings are sanitized by HTML Sanitization components. A remote attacker can create a specially crafted URL, trick the victim into opening it, take actions on the targeted site or read restricted content and obtain sensitive information with elevated privileges.
Successful exploitation of the vulnerability results in arbitrary code execution on the vulnerable system.
Note: the vulnerability was being actively exploited.