The Simple Download Monitor plugin before 3.5.4 for WordPress has XSS via the sdmuploadthumbnail (aka File Thumbnail) parameter in an edit action to wp-admin/post.php.
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2018-5212.json"
[ { "events": [ { "introduced": "0" }, { "last_affected": "3.5.4" } ] }, { "events": [ { "introduced": "0" }, { "fixed": "3.5.4" } ] } ]