URLs using “javascript:” have the protocol removed when pasted into the address bar to protect users from cross-site scripting (XSS) attacks, but in certain circumstances this removal was not performed. This could allow users to be socially engineered to run an XSS attack against themselves. This vulnerability affects Opera for Android versions below 61.0.3076.56532.

Opera for Android before 54.0.2669.49432 is vulnerable to a sandboxed cross-origin iframe bypass attack. By using a service working inside a sandboxed iframe it is possible to bypass the normal sandboxing attributes. This allows an attacker to make forced redirections without any user interaction from a third-party context.

The HTTPS protocol does not consider the role of the TCP congestion window in providing information about content length, which makes it easier for remote attackers to obtain cleartext data by leveraging a web-browser configuration in which third-party cookies are sent, aka a "HEIST" attack.

Untrusted search path vulnerability in Opera before 10.62 allows local users to gain privileges via a Trojan horse dwmapi.dll file in the current working directory, as demonstrated by a directory that contains a .htm, .mht, .mhtml, .xht, .xhtm, or .xhtl file. NOTE: some of these details are obtained from third party information.

The HTML parsing engine in Opera before 9.63 allows remote attackers to execute arbitrary code via crafted web pages that trigger an invalid pointer calculation and heap corruption.

The links panel in Opera before 9.62 processes Javascript within the context of the "outermost page" of a frame, which allows remote attackers to inject arbitrary web script or HTML via cross-site scripting (XSS) attacks.

Opera before 9.62 allows remote attackers to execute arbitrary commands via the History Search results page, a different vulnerability than CVE-2008-4696.

Cross-site scripting (XSS) vulnerability in Opera.dll in Opera before 9.61 allows remote attackers to inject arbitrary web script or HTML via the anchor identifier (aka the "optional fragment"), which is not properly escaped before storage in the History Search database (aka md.dat).

Unspecified vulnerability in Opera before 9.52 on Windows, when registered as a protocol handler, allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via unknown vectors in which Opera is launched by other applications.

Opera allows web sites to set cookies for country-specific top-level domains that have DNS A records, such as co.tv, which could allow remote attackers to perform a session fixation attack and hijack a user's HTTP session, aka "Cross-Site Cooking."

Unspecified vulnerability in Opera before 9.51 on Windows allows attackers to execute arbitrary code via unknown vectors.

Opera before 9.27 allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via a crafted newsfeed source, which triggers an invalid memory access.

Unspecified vulnerability in Opera before 9.27 has unknown impact and attack vectors related to "keyboard handling of password inputs."

Opera, probably before 7.50, sends Referer headers containing https:// URLs in requests for http:// URLs, which allows remote attackers to obtain potentially sensitive information by reading Referer log data.