Opera cannot properly restrict modifications to cookies established in HTTPS sessions, which allows man-in-the-middle attackers to overwrite or delete arbitrary cookies via a Set-Cookie header in an HTTP response, related to lack of the HTTP Strict Transport Security (HSTS) includeSubDomains feature, aka a "cookie forcing" issue.

Opera before 10.10 permits cross-origin loading of CSS stylesheets even when the stylesheet download has an incorrect MIME type and the stylesheet document is malformed, which allows remote attackers to obtain sensitive information via a crafted document.

Opera executes DOM calls in response to a javascript: URI in the target attribute of a submit element within a form contained in an inline PDF file, which might allow remote attackers to bypass intended Adobe Acrobat JavaScript restrictions on accessing the document object, as demonstrated by a web site that permits PDF uploads by untrusted users, and therefore has a shared document.domain between the web site and this javascript: URI. NOTE: the researcher reports that Adobe's position is "a PDF file is active content."

Sun Java Runtime Environment (JRE) in JDK and JRE 6 Update 2 and earlier, JDK and JRE 5.0 Update 12 and earlier, SDK and JRE 1.4.2_15 and earlier, and SDK and JRE 1.3.1_20 and earlier, when Firefox or Opera is used, allows remote attackers to violate the security model for JavaScript outbound connections via a multi-pin DNS rebinding attack dependent on the LiveConnect API, in which JavaScript download relies on DNS resolution by the browser, but JavaScript socket operations rely on separate DNS resolution by a Java Virtual Machine (JVM), a different issue than CVE-2007-5273. NOTE: this is similar to CVE-2007-5232.