The Opera Mini application 47.1.2249.129326 for Android allows remote attackers to spoof the Location Permission dialog via a crafted web site.

Opera Mini for Android below 53.1 displays URL left-aligned in the address field. This allows a malicious attacker to craft a URL with a long domain name, e.g. www.safe.opera.com.attacker.com. With the URL being left-aligned, the user will only see the front part (e.g. www.safe.opera.com…) The exact amount depends on the phone screen size but the attacker can craft a number of different domains and target different phones. Starting with version 53.1 Opera Mini displays long URLs with the top-level domain label aligned to the right of the address field which mitigates the issue.

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 Touch for iOS before version 2.4.5 is vulnerable to an address bar spoofing attack. The vulnerability allows a malicious page to trick the browser into showing an address of a different page. This may allow the malicious page to impersonate another page and trick a user into providing sensitive data.

Opera through 53 on Android allows Address Bar Spoofing. Characters from several languages are displayed in Right-to-Left order, due to mishandling of several Unicode characters. The rendering mechanism, in conjunction with the "first strong character" concept, may improperly operate on a numerical IP address or an alphabetic string, leading to a spoofed URL.

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.

Opera Mini for Android allows attackers to bypass intended restrictions on .apk file download/installation via an RTLO (aka Right to Left Override) approach, as demonstrated by misinterpretation of malicious%E2%80%AEtxt.apk as maliciouskpa.txt. This affects 44.1.2254.142553, 44.1.2254.142659, and 44.1.2254.143214.

The Opera Mini application through 16.0.14 for iOS has a UXSS vulnerability that can be triggered by performing navigation to a javascript: URL.

Opera before 57.0.3098.106 is vulnerable to a DLL Search Order hijacking attack where an attacker can send a ZIP archive composed of an HTML page along with a malicious DLL to the target. Once the document is opened, it may allow the attacker to take full control of the system from any location within the system. The issue lies in the loading of the shcore.dll and dcomp.dll files: these files are being searched for by the program in the same system-wide directory where the HTML file is executed.

In the WebRTC component in Opera 51.0.2830.55, after visiting a web site that attempts to gather complete client information (such as https://ip.voidsec.com), the browser can disclose a private IP address in a STUN request.

Opera Mini 13 and Opera Stable 36 allow remote attackers to spoof the displayed URL via a crafted HTML document, related to the about:blank URL.

Characters from languages are such as Arabic, Hebrew are displayed from RTL (Right To Left) order in Opera 37.0.2192.105088 for Android, due to mishandling of several unicode characters such as U+FE70, U+0622, U+0623 etc and how they are rendered combined with (first strong character) such as an IP address or alphabet could lead to a spoofed URL. It was noticed that by placing neutral characters such as "/", "?" in filepath causes the URL to be flipped and displayed from Right To Left. However, in order for the URL to be spoofed the URL must begin with an IP address followed by neutral characters as omnibox considers IP address to be combination of punctuation and numbers and since LTR (Left To Right) direction is not properly enforced, this causes the entire URL to be treated and rendered from RTL (Right To Left). However, it doesn't have be an IP address, what matters is that first strong character (generally, alphabetic character) in the URL must be an RTL character.

The TLS protocol 1.2 and earlier supports the rsa_fixed_dh, dss_fixed_dh, rsa_fixed_ecdh, and ecdsa_fixed_ecdh values for ClientCertificateType but does not directly document the ability to compute the master secret in certain situations with a client secret key and server public key but not a server secret key, which makes it easier for man-in-the-middle attackers to spoof TLS servers by leveraging knowledge of the secret key for an arbitrary installed client X.509 certificate, aka the "Key Compromise Impersonation (KCI)" issue.

The HTTP/2 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.

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.

Unspecified vulnerability in Opera Mail before 2016-02-16 on Windows allows user-assisted remote attackers to execute arbitrary code via a crafted e-mail message.

The TLS protocol 1.2 and earlier, when a DHE_EXPORT ciphersuite is enabled on a server but not on a client, does not properly convey a DHE_EXPORT choice, which allows man-in-the-middle attackers to conduct cipher-downgrade attacks by rewriting a ClientHello with DHE replaced by DHE_EXPORT and then rewriting a ServerHello with DHE_EXPORT replaced by DHE, aka the "Logjam" issue.

Opera before 19 on Mac OS X allows user-assisted remote attackers to spoof the address bar via vectors involving a drag-and-drop operation.

The intent: URL implementation in Opera before 18 on Android allows attackers to read local files by leveraging an interaction error, as demonstrated by reading stored cookies.

Cross-site scripting (XSS) vulnerability in Opera before 15.00 allows remote attackers to inject arbitrary web script or HTML by leveraging UTF-8 encoding.

Unspecified vulnerability in Opera before 12.15 has unknown impact and attack vectors, related to a "moderately severe issue."

Opera before 12.15 does not properly block top-level domains in Set-Cookie headers, which allows remote attackers to obtain sensitive information by leveraging control of a different web site in the same top-level domain.

The TLS implementation in Opera before 12.13 does not properly consider timing side-channel attacks on a MAC check operation during the processing of malformed CBC padding, which allows remote attackers to conduct distinguishing attacks and plaintext-recovery attacks via statistical analysis of timing data for crafted packets, a related issue to CVE-2013-0169.

Opera before 12.13 does not send CORS preflight requests in all required cases, which allows remote attackers to bypass a CSRF protection mechanism via a crafted web site that triggers a CORS request.

Opera before 12.13 allows remote attackers to execute arbitrary code via crafted clipPaths in an SVG document.