SilverStripe CMS before 3.6.1 has XSS via an SVG document that is mishandled by (1) the Insert Media option in the content editor or (2) an admin/assets/add pathname, as demonstrated by the admin/pages/edit/EditorToolbar/MediaForm/field/AssetUploadField/upload URI, aka issue SS-2017-017.
{
"versions": [
{
"introduced": "0"
},
{
"last_affected": "3.6.0"
}
]
}