GreyMagic Security Advisory GM#009-OP – Opera versions 7.53 and below on Windows, Linux and Macintosh have a flaw that allows an attacker the ability to figure out whether or not a file or directory exists.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/34083/gm009-op.txt
Source: https://packetstormsecurity.com/files/34083/gm009-op.txt.html