The Twitter Bootstrap Collapse aka Accordian Shortcode WordPress plugin through 1.0 does not validate and escape some of its shortcode attributes before outputting them back in a page/post where the shortcode is embed, which could allow users with the contributor role and above to perform Stored Cross-Site Scripting attacks.
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.