Description

In May 2025, a highly vulnerable vulnerability CVE-2025-47539 with CVSS 9.8 was disclosed in popular WordPress plugin Eventin by Themewinter. The event RSVP, ticketing, and calendar management plugin installed on more than 10,000 sites had a vulnerability in the REST API endpoint via which unauthenticated privilege escalation was occurring. Taking advantage of this vulnerability, an attacker is able to upload a malicious CSV to establish an administrator-level account with absolutely no kind of authentication whatsoever, essentially taking over the site. The vulnerability was responsibly discovered by security researcher Denver Jackson and he was awarded a $600 bounty through the Patchstack Zero Day Initiative. The root issue was a mistake in the setup of a permission check in the plugin's /wp-json/eventin/v2/speakers/import endpoint. Although it did contain a permission callback function, the function (import_item_permissions_check) was incorrectly coded so that it always passed and di?d provide any access restriction to the endpoint. By posting a specially designed CSV file with a POST request, the plugin importer ran code that impacted user roles as specified in the posted file, for instance, making the attacker an administrator. This provided complete backend access, data manipulation control, and site operation management. Administrators of sites that use the Eventin plugin are urged to upgrade to version 4.0.27 as soon as possible. Administrators should also carefully scan admin user lists for unauthorized accounts, reset admin passwords, and turn on two-factor authentication (2FA) for all admins. Ongoing log monitoring and access reviews will assist in detecting indicators of compromise. Regular plugin updates and secure development will be necessary to protect against such major vulnerabilities in the future.