Any website has vulnerabilities and it doesn’t matter what platform you choose, however; WordPress has taken steps that prove how committed they are to your websites security.
Recently, Jetpack had a vulnerability that needed dealt with. They worked hard to get this patched and while they were doing so WordPress put up temporary blocks to protect your site from these vulnerabilities.
Now that the patches are complete WordPress even went as far as to disconnect self-hosted websites that did not yet update their Jetpack’s plugin security updates. So if you are one of those users your site has been disconnected and is probably broken in a few places wherever you are using the Jetpack plugin features. So get in there and update your Jetpack plugin and then reconnect it so that your broken bits can be restored.