The mappress-google-maps-for-wordpress plugin before 2.53.9 for WordPress does not correctly implement AJAX functions with nonces (or capability checks), leading to remote code execution.
https://www.wordfence.com/blog/2020/04/critical-vulnerabilities-patched-in-mappress-maps-plugin/
https://wordpress.org/plugins/mappress-google-maps-for-wordpress/#developers