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 11.10 allows remote attackers to cause a denial of service (application crash) via an HTML document that has an empty parameter value for an embedded Java applet.

Opera before 11.10 does not properly handle hidden animated GIF images, which allows remote attackers to cause a denial of service (CPU consumption) via an image file that triggers continual repaints.

Unspecified vulnerability in Opera before 11.10 allows remote attackers to cause a denial of service (application crash) via unknown content on a web page, as demonstrated by games on zylom.com.

Unspecified vulnerability in Opera before 11.10 allows remote attackers to cause a denial of service (application crash) via unknown content on a web page, as demonstrated by futura-sciences.com, seoptimise.com, and mitosyfraudes.org.

Unspecified vulnerability in Opera before 11.10 allows remote attackers to cause a denial of service (application crash) via unknown content on a web page, as demonstrated by a certain Tomato Firmware page.

The Cascading Style Sheets (CSS) implementation in Opera before 11.10 allows remote attackers to cause a denial of service (application crash) via vectors involving use of the :hover pseudo-class, in conjunction with transforms, for a floated element.

Opera before 11.10 allows remote attackers to hijack (1) searches and (2) customizations via unspecified third party applications.

Unspecified vulnerability in Opera before 11.11 allows remote attackers to cause a denial of service (application crash) via vectors involving a Certificate Revocation List (CRL) file, as demonstrated by the multicert-ca-02.crl file.

Opera before 11.11 does not properly handle destruction of a Silverlight instance, which allows remote attackers to cause a denial of service (application crash) via a web page, as demonstrated by vod.onet.pl.

The Cascading Style Sheets (CSS) implementation in Opera before 11.11 does not properly handle the column-count property, which allows remote attackers to cause a denial of service (infinite repaint loop and application hang) via a web page, as demonstrated by an unspecified Wikipedia page.

Opera before 11.11 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 occurring after the opening of a popup of the Easy Sticky Note extension.

Unspecified vulnerability in Opera before 11.11 allows remote attackers to cause a denial of service (application crash) via unknown content on a web page, as demonstrated by www.falk.de.

Opera before 11.11 does not properly implement FRAMESET elements, which allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption) via vectors related to page unload.

Unspecified vulnerability in the DOM implementation in Opera before 11.50 allows remote attackers to cause a denial of service (application crash) via unknown content on a web page, as demonstrated by live.com.

Opera before 11.50 allows remote attackers to cause a denial of service (application crash) by using "injected script" to set the SRC attribute of an IFRAME element.

Opera before 11.50 allows remote attackers to cause a denial of service (application crash) via a SELECT element that contains many OPTION elements.

Opera before 11.50 allows user-assisted remote attackers to cause a denial of service (application hang) via a large table, which is not properly handled during a print preview.

Unspecified vulnerability in the SVG BiDi implementation in Opera before 11.50 allows remote attackers to cause a denial of service (application crash or hang) via unknown vectors.

Unspecified vulnerability in the Web Workers implementation in Opera before 11.50 allows remote attackers to cause a denial of service (application crash) via unknown vectors.