The sandbox protection mechanism in Microsoft Internet Explorer 9 allows remote attackers to cause a denial of service (memory corruption) or possibly have unspecified other impact via unknown vectors, as demonstrated against Adobe Flash Player by VUPEN during a Pwn2Own competition at CanSecWest 2013.
The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.