The Saan World Clock WordPress plugin through 1.8 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/f4e4b4a2-c7cb-42ce-9d5b-bd84efcbf54d