Opera before 10.01 does not properly restrict HTML in a (1) RSS or (2) Atom feed, which allows remote attackers to conduct cross-site scripting (XSS) attacks, and conduct cross-zone scripting attacks involving the Feed Subscription Page to read feeds or create feed subscriptions, via a crafted feed, related to the rendering of the application/rss+xml content type as "scripted content."

Opera before 10.00 trusts root X.509 certificates signed with the MD2 algorithm, which makes it easier for man-in-the-middle attackers to spoof arbitrary SSL servers via a crafted server certificate.

Opera before 10.00 does not properly handle a (1) '\0' character or (2) invalid wildcard character in a domain name in the subject's Common Name (CN) field of an X.509 certificate, which allows man-in-the-middle attackers to spoof arbitrary SSL servers via a crafted certificate issued by a legitimate Certification Authority.

Opera before 10.00 does not properly display all characters in Internationalized Domain Names (IDN) in the address bar, which allows remote attackers to spoof URLs and conduct phishing attacks, related to Unicode and Punycode.

Opera before 10.00 on Linux, Solaris, and FreeBSD does not properly implement the "INPUT TYPE=file" functionality, which allows remote attackers to trick a user into uploading an unintended file via vectors involving a "dropped file."

Opera before 10.00, when a collapsed address bar is used, does not properly update the domain name from the previously visited site to the currently visited site, which might allow remote attackers to spoof URLs.

Opera 9.64 allows remote attackers to cause a denial of service (application crash) via an XML document containing a long series of start-tags with no corresponding end-tags. NOTE: it was later reported that 9.52 is also affected.

Unspecified vulnerability in Opera before 9.64 has unknown impact and attack vectors, related to a "moderately severe issue."

Opera before 9.64 allows remote attackers to execute arbitrary code via a crafted JPEG image that triggers memory corruption.

Unspecified vulnerability in Opera before 9.63 allows remote attackers to "reveal random data" via unknown vectors.