Unspecified vulnerability in Opera before 12.00 on Mac OS X has unknown impact and attack vectors, related to a "moderate severity issue."

Opera before 12.00 Beta allows remote attackers to cause a denial of service (application crash) via a web page that contains invalid character encodings.

Opera before 11.65 does not properly restrict the reading of JSON strings, which allows remote attackers to perform cross-domain loading of JSON resources and consequently obtain sensitive information via a crafted web site.

Opera before 12.00 Beta allows remote attackers to cause a denial of service (application crash) via crafted characters in domain names, as demonstrated by "IDNA2008 tests."

Opera before 12.00 Beta allows remote attackers to cause a denial of service (application crash) via crafted WebGL content, as demonstrated by a codeflow.org WebGL demo.

Opera before 11.65 does not ensure that the address field corresponds to the displayed web page during blocked navigation, which makes it easier for remote attackers to conduct spoofing attacks by detecting and preventing attempts to load a different web page.

Opera before 12.00 Beta allows user-assisted remote attackers to cause a denial of service (application hang) via JavaScript code that changes a form before submission.

Opera before 11.65 does not ensure that the address field corresponds to the displayed web page during unusually timed changes to this field, which makes it easier for user-assisted remote attackers to conduct spoofing attacks via vectors involving navigation, reloads, and redirects.

Opera before 12.00 Beta allows user-assisted remote attackers to cause a denial of service (application crash) via a crafted web page that is not properly handled during a reload, as demonstrated by a "multiple origin camera test" page.

Opera before 11.65 does not properly restrict the opening of a pop-up window in response to the first click of a double-click action, 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.