An unauthenticated attacker can create a malicious link which they can make publicly available. When an authenticated victim clicks on this malicious link, input data will be used by the web site page generation to create content which when executed in the victim's browser (XXS) or transmitted to another server (SSRF) gives the attacker the ability to execute arbitrary code on the server fully compromising confidentiality, integrity and availability.
The product receives data from an upstream component, but does not completely filter special elements before sending it to a downstream component.