A vulnerability has been recently discovered in OpenSSL library used by webservers to support HTTPS protocol.
This vulnerability called Heartbleed has been published before the patch was released. Unfortunately the webmasters have not enough time to protect their website.
As you may have notice, jdCaptcha website is using HTTPS to protect the exchange of your password when you log in. The jdCaptcha website is not exposed and has never been exposed to this vulnerability, you don't need to change your password or anything. You can keep surfing safely on jdCaptcha website.