Adenion Blog2Social plugin for WordPress before 9.1.0 exposes the email addresses of all registered WordPress users to low-privileged accounts. The b2s_search_user AJAX handler in includes/Ajax/Get.php invokes B2S_Tools::searchUser() in includes/Tools.php, which returns the email address of every matching user without restricting access to callers holding the list_users capability, allowing any user with the edit_posts capability to retrieve user email addresses including those of administrators.

Adenion Blog2Social plugin for WordPress before 9.1.0 exposes the email addresses of all registered WordPress users to low-privileged accounts. The b2s_search_user AJAX handler in includes/Ajax/Get.php invokes B2S_Tools::searchUser() in includes/Tools.php, which returns the email address of every matching user without restricting access to callers holding the list_users capability, allowing any user with the edit_posts capability to retrieve user email addresses including those of administrators.