Risk: High
Both Mac and Windows operating systems are believed to be at risk due to a buffer overflow flaw.
The vulnerability is caused due to a boundary error when handling RTSP replies. If successfully exploited, QuickTime player may crash at a memory location and may then be controlled by an attacker.
In order for an attacker to execute arbitary code, a user must be tricked into opening a malicious QTL file or visit a malicious web site.
Apple have not yet patched this vulnerability and users have been urged to not browse untrusted websites, open malicious QTL files, or follow untrusted links.