Blog2Social vulnerabilities

The Blog2Social plugin for WordPress before version 9.1.0 exposes the email addresses of all registered users to low-privileged accounts. The b2s_search_user AJAX handler in includes/Ajax/Get.php calls 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.

The Blog2Social plugin for WordPress before version 9.1.0 allows low-privileged users to enumerate WordPress user accounts. The b2s_get_select_mandant_user AJAX handler in includes/Ajax/Get.php resolves arbitrary user IDs supplied in the owner parameter to display names without verifying that the caller is authorized to read user account data, allowing any user with the edit_posts capability to map WordPress user IDs to display names and confirm account existence for arbitrary IDs.

The vulnerability allows an unauthenticated attacker to perform XSS attacks in Blog2Social version 8.9.2 and earlier. The attack can be carried out without authentication, increasing the risk of exploitation.

Missing authorization in the Blog2Social plugin for WordPress (up to version 8.8.3). Authenticated attackers with Subscriber access can modify, reschedule, or delete other users' scheduled social media posts by manipulating the b2s_id parameter.