An elevation of privilege vulnerability exists when Microsoft SharePoint Server does not properly sanitize a specially crafted authentication request to an affected SharePoint server. An attacker who successfully exploited this vulnerability could execute malicious code on a vulnerable server in the context of the SharePoint application pool account. To exploit this vulnerability, an authenticated attacker would need to create a page specifically designed to cause a server-side request. The attacker would then send a specially-crafted message to perform a server-side request forgery attack. The update addresses the vulnerability by modifying how Microsoft SharePoint Server manages server authentication.
Is the Preview Pane an attack vector for this vulnerability? No, the Preview Pane is not an attack vector.