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.
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.
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 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.
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.
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.
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.