TL:DR If you are using my Temboz feed reader, please update as soon as possible to version 4.4.0 or later.
This is somewhat related to the last security advisory for Temboz. Fields like article title, author or tags, or feed title or description that are supposed to be plain text (not even HTML) were not being sanitized. For XSS. The effect was demonstrated by this article in BoingBoing.
Once again I apologize for potentially exposing you to XSS attacks via malicious feeds, and I would recommend you subscribe to my RSS feed for it so you can get important announcements like this one in the future.