CVE 2007-2383

The Prototype (prototypejs) framework before 1.5.1 RC3 exchanges data using JavaScript Object Notation (JSON) without an associated protection scheme, which allows remote attackers to obtain the data via a web page that retrieves the data through a URL in the SRC attribute of a SCRIPT element and captures the data using other JavaScript code, aka "JavaScript Hijacking."

See the CVE page on Mitre.org for more details.