Except where noted in the syntax, CFML tags do not require an end tag. However, all CFML tags (except CFELSE and CFELSEIF) can accept an optional end tag, as follows:
<CFABORT/>
<CFABORT></CFABORT> <!--- The following will produce a validation error <CFABORT> </CFABORT> --->
You do not typically code optional end tags.