admin/partials/wp-splashing-admin-main.php in the Splashing Images plugin (wp-splashing-images) before 2.1.1 for WordPress allows authenticated (administrator, editor, or author) remote attackers to conduct PHP Object Injection attacks via crafted serialized data in the 'session' HTTP GET parameter to wp-admin/upload.php.
https://wpvulndb.com/vulnerabilities/9015
https://plugins.trac.wordpress.org/changeset/1807349/wp-splashing-images