HTML injection attack is closely related to Cross-site Scripting (XSS). HTML injection uses HTML to deface the page. XSS, as the name implies, injects JavaScript into the page. Both attacks exploit insufficient validation of user input.
Prior to microweber/microweber v1.2.20, due to improper neutralization of input, an attacker can steal tokens to perform cross-site request forgery, fetch contents from same-site and redirect a user.