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.
https://wpscan.com/vulnerability/c3be5990-ca89-4ac4-baae-49af55df9d57/