Opera 3.2.1 allows remote attackers to cause a denial of service (application crash) via a URL that contains an extra / in the http:// tag.
Buffer overflow in Opera 6.01 allows remote attackers to cause a denial of service (crash) via an IMG tag with large width and height attributes.
Opera 5.0 for Linux does not properly handle malformed HTTP headers, which allows remote attackers to cause a denial of service, possibly with a header whose value is the same as a MIME header name.