Opera before 12.10 does not properly implement the Cross-Origin Resource Sharing (CORS) specification, which allows remote attackers to bypass intended page-content restrictions via a crafted request.

The X.509 certificate-validation functionality in the https implementation in Opera before 12.10 allows remote attackers to trigger a false indication of successful revocation-status checking by causing a failure of a single checking service.

Opera before 11.67 and 12.x before 12.02 allows remote attackers to cause truncation of a dialog, and possibly trigger downloading and execution of arbitrary programs, via a crafted web site.

Opera before 12.01 allows remote attackers to cause a denial of service (application crash) via a crafted web site, as demonstrated by the Lenovo "Shop now" page.

Unspecified vulnerability in Opera before 12.01 on Windows and UNIX, and before 11.66 and 12.x before 12.01 on Mac OS X, has unknown impact and attack vectors, related to a "low severity issue."

Opera before 12.01 on Windows and UNIX, and before 11.66 and 12.x before 12.01 on Mac OS X, does not properly escape characters in DOM elements, which makes it easier for remote attackers to bypass cross-site scripting (XSS) protection mechanisms via a crafted HTML document.

Opera before 12.01 on Windows and UNIX, and before 11.66 and 12.x before 12.01 on Mac OS X, allows user-assisted remote attackers to trick users into downloading and executing arbitrary files via a small window for the download dialog, a different vulnerability than CVE-2012-1924.

Opera before 12.01 on Windows and UNIX, and before 11.66 and 12.x before 12.01 on Mac OS X, ignores some characters in HTML documents in unspecified circumstances, which makes it easier for remote attackers to conduct cross-site scripting (XSS) attacks via a crafted document.

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.