EllisLab released an update to the Twitter Timeline plugin to close a security hole. It is a critical update so everyone should update to the latest version of the plugin.
Pascal Kriete posted to the EE blog:
We wanted to give you a heads up that we updated the Twitter Timeline plugin to address a security issue. We consider this one critical as it can result in unexpected information disclosure. Both ExpressionEngine 1 and 2 versions were affected. All users are encouraged to update to the latest version (tell your friends).
Read Pascal’s post to learn about the update: Twitter Timeline Plugin Security Update