Opera versions below 9.25 are susceptible to a heap-based buffer overflow that allows for a denial of service and possibly code execution.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/66750/aklink-sa-2008-006-opera-heap-overflow.txt
Source: https://packetstormsecurity.com/files/66750/aklink-sa-2008-006-opera-heap-overflow.txt.html