In affected versions of the Webmention plugin, the 'MF2::parse_authorpage' function is leveraged through the 'Receiver::post' function to execute Server-Side Request Forgery. This vulnerability lets unauthenticated users manipulate the web server into forwarding requests to arbitrary URLs. The consequences of such exploitation include the possibility of attackers accessing sensitive information from internal services not typically accessible externally. Moreover, this can lead to the compromise of internal network configurations or data leakage if improperly secured internal services are available. Attackers might also manage to conduct further exploits by gaining sensitive information from the internal environments.

Administrators should immediately implement firewall rules to limit outgoing requests from the web server hosting the WordPress installation. Additionally, disabling or removing the Webmention plugin until a fix is applied can prevent potential exploits. It is also advisable to regularly review and monitor server logs for any unauthorized requests to unexpected remote services.