Opera 7.54 allows remote attackers to cause a denial of service (application crash from memory exhaustion), as demonstrated using Javascript code that continuously creates nested arrays and then sorts the newly created arrays.

Opera 7.54 and earlier does not properly limit an applet's access to internal Java packages from Sun, which allows remote attackers to gain sensitive information, such as user names and the installation directory.

Opera 7.54 and earlier allows remote attackers to spoof file types in the download dialog via dots and non-breaking spaces (ASCII character code 160) in the (1) Content-Disposition or (2) Content-Type headers.

Opera 7.54 and earlier uses kfmclient exec to handle unknown MIME types, which allows remote attackers to execute arbitrary code via a shortcut or launcher that contains an Exec entry.

Opera allows remote attackers to cause a denial of service (invalid memory reference and application crash) via a web page or HTML email that contains a TBODY tag with a large COL SPAN value, as demonstrated by mangleme.