In the rcfilters plugin 2.1.6 for Roundcube, XSS exists via the _whatfilter and _messages parameters (in the Filters section of the settings).
{
"cpe": "cpe:2.3:a:rcfilters_project:rcfilters:2.1.6:*:*:*:*:roundcube:*:*",
"extracted_events": [
{
"introduced": "2.1.6"
},
{
"last_affected": "2.1.6"
}
],
"source": "CPE_STRING"
}