Improper Neutralization of Input During Web Page Generation (XSS or 'Cross-site Scripting') vulnerability in Bootstrap allows Cross-Site Scripting (XSS).This issue affects Bootstrap: from 3.4.1 before 4.0.0.
The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.