Zulip Server before 2.1.3 allows reverse tabnabbing via the Markdown functionality.
{
"extracted_events": [
{
"introduced": "0"
},
{
"last_affected": "2.1.3"
}
],
"cpe": "cpe:2.3:a:zulip:zulip_server:*:*:*:*:*:*:*:*",
"source": "CPE_RANGE"
}