It appears to be a false positive. If I just combine the jquery with the jquery UI javascript files into one document it shows the error, but scanning each individually doesn't.
However, it does appear that updating from jquery 1.11 to jquery 1.12 fixes the error, so I'll get it updated. Here are the files you can update to fix the issue in the meantime.
Just replace:
/webassist/kcfinder/js/000._jquery.js
/webassist/kcfinder/js/002._jqueryui.js