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.

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 12.10 does not properly handle incorrect size data in a WebP image, which allows remote attackers to obtain potentially sensitive information from process memory by using a crafted image as the fill pattern for a canvas.

Opera before 12.10 follows Internet shortcuts that are referenced by a (1) IMG element or (2) other inline element, which makes it easier for remote attackers to conduct phishing attacks via a crafted web site, as exploited in the wild in November 2012.

Cross-site scripting (XSS) vulnerability in Opera before 12.10 allows remote attackers to inject arbitrary web script or HTML via crafted JavaScript code that overrides methods of unspecified native objects in documents that have different origins.

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 on UNIX uses weak permissions for the profile directory, which allows local users to obtain sensitive information by reading a (1) cache file, (2) password file, or (3) configuration file, or (4) possibly gain privileges by modifying or overwriting a configuration file.

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.