Heap-based buffer overflow in Opera before 12.11 allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption) via a long HTTP response.

Opera before 12.12 allows remote attackers to spoof the address field via a high rate of HTTP requests.

Opera before 12.12 does not properly allocate memory for GIF images, which allows remote attackers to execute arbitrary code or cause a denial of service (memory overwrite) via a malformed image.

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.

Cross-site scripting (XSS) vulnerability in Opera before 12.10 allows remote attackers to inject arbitrary web script or HTML via vectors involving an unspecified sequence of loading of documents and loading of data: URLs.

Opera before 12.11 allows remote attackers to determine the existence of arbitrary local files via vectors involving web script in an error page.

Opera before 11.60 allows remote attackers to spoof the address bar via unspecified homograph characters, a different vulnerability than CVE-2010-2660.

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.

Opera before 11.65 does not ensure that keyboard sequences are associated with a visible window, which makes it easier for user-assisted remote attackers to conduct cross-site scripting (XSS) attacks or execute arbitrary code via a crafted web site, related to a "hidden keyboard navigation" issue.

Opera before 12.00 Beta allows remote attackers to cause a denial of service (memory consumption or application hang) via an IFRAME element that uses the src="#" syntax to embed a parent document.