Opera before 9.0 does not reset the SSL security bar after displaying a download dialog from an SSL-enabled website, which allows remote attackers to spoof a trusted SSL certificate from an untrusted website and facilitates phishing attacks.
Integer overflow in Opera 8.54 and earlier allows remote attackers to execute arbitrary code via a JPEG image with large height and width values, which causes less memory to be allocated than intended.
Integer signedness error in Opera before 8.54 allows remote attackers to execute arbitrary code via long values in a stylesheet attribute, which pass a length check. NOTE: a sign extension problem makes the attack easier with shorter strings.
Opera 8.02 and earlier allows remote attackers to cause a denial of service (client crash) via (1) a crafted HTML file with a "content: url(0);" style attribute, a "bodyA" tag, a long string, and a "u" tag with a long attribute, as demonstrated by opera.html; and (2) a BGSOUND element with a "margin:-99;" STYLE attribute.
Opera before 8.51, when running on Windows with Input Method Editor (IME) installed, allows remote attackers to cause a denial of service (persistent application crash) by bookmarking a site with a long title.
Opera before 8.51 on Linux and Unix systems allows remote attackers to execute arbitrary code via shell metacharacters (backticks) in a URL that another product provides in a command line argument when launching Opera.
The mail client in Opera before 8.50 opens attached files from the user's cache directory without warning the user, which might allow remote attackers to inject arbitrary web script and spoof attachment filenames.
Opera before 8.50 allows remote attackers to spoof the content type of files via a filename with a trailing "." (dot), which might allow remote attackers to trick users into processing dangerous content.
A design error in Opera 8.01 and earlier allows user-assisted attackers to execute arbitrary code by overlaying a malicious new window above a file download dialog box, then tricking the user into double-clicking on the "Run" button, aka "link hijacking".