WordPress before 5.2.4 is vulnerable to poisoning of the cache of JSON GET requests because certain requests lack a Vary: Origin header.
{ "availability": "No subscription required", "ubuntu_priority": "medium", "binaries": [ { "binary_version": "5.2.4+dfsg1-1", "binary_name": "wordpress" }, { "binary_version": "5.2.4+dfsg1-1", "binary_name": "wordpress-l10n" }, { "binary_version": "5.2.4+dfsg1-1", "binary_name": "wordpress-theme-twentynineteen" }, { "binary_version": "5.2.4+dfsg1-1", "binary_name": "wordpress-theme-twentyseventeen" }, { "binary_version": "5.2.4+dfsg1-1", "binary_name": "wordpress-theme-twentysixteen" } ] }