How Opera’s Security team helps make the web safer through responsible disclosure

Security How Opera’s Security team helps make the web safer through responsible disclosure Share April 17th, 2026 Hi everyone! At Opera, we have 30 years of experience in building safe and secure browsers. Our seasoned Security team collaborates internally as well as with external researchers to...

Fuzzing HTTP Proxies: Privoxy, Part 1

Research Fuzzing HTTP Proxies: Privoxy, Part 1 Share May 17th, 2021 Here at Opera, we’re always looking for ways to improve the browsing experience of our users with speed and usability. Perhaps more importantly though, we also look for ways to improve users’ privacy and security. While we...

Certificate update

Security Certificate update Share December 9th, 2013 Last week we became aware of the existence of several unauthorized security certificates, issued in violation of rules for creation of such certificates. The certificates chained back to a French certificate authority, ANSSI, and had been signe...

Email passwords are not immediately deleted when deleting private data – Opera Security Advisories

Email passwords are not immediately deleted when deleting private data – Opera Security Advisories OPCOM Team | January 26, 2011 Severity Moderate Description When using “Delete Private Data” and selecting the option to “Clear all email account passwords”, the passwords were not deleted...

Reloads and redirects can allow spoofing and cross site scripting

Scripts on a page are supposed to be restricted so that they can only interact with other pages from the same domain and security context. Carefully timed reloads and redirects, when combined with appropriate caching, can cause scripts to execute in the wrong security context in Opera. This allow...

Double-clicking a link can unexpectedly run a program from the Internet

When a user clicks a link on a Web page that points to an executable file, Opera will show a download dialog to allow the user to download it. The dialog will allow the user to choose to run the executable directly. If the user accidentally double clicks, the second click will activate whatever i...

Pages can trick users into uploading files

On some Linux or Unix installations, Opera would pass a dropped file to a file input, making it possible for a page to trick users to upload files without the user's knowledge...

Adress bar is not always updated correctly when collapsed

The collapsed Address bar can in some cases temporarily show the previous domain instead of the domain of the present site...

Specially crafted addresses can execute arbitrary code

If a malicious page redirects Opera to a specially crafted address URL, it can cause Opera to crash. Given sufficient address content, the crash could cause execution of code controlled by the attacking page...

Scripts can overwrite functions on pages from other domains

When accesing frames from different Web sites, specially crafted scripts can bypass the same-origin policy, and overwrite functions from those frames. If scripts on the page then run those functions, this can cause the script of the attacker's choice to run in the context of the target Web site...

A malicious torrent can cause Opera to execute arbitrary code

Removing a specially crafted torrent from the download managercan crash Opera. The crash is caused by an erroneous memoryaccess.An attacker needs to entice the user to accept the maliciousBitTorrent download, and later remove it from Opera's downloadmanager. To inject code, additional means will...

Very large link addresses can cause Opera to crash

An extremely long link address can cause Opera to crash.A specially crafted long link could cause malicious codeto be run on the user's computer...

A forged SSL server certificate can be accepted by Opera as a valid certificate

A specially crafted digital certificate can bypass Opera'scertificate signature verification. Forged certificatescan contain any false information the forger chooses, andOpera will still present it as valid. Opera will not presentany warning dialogs in this case, and the security statuswill be th...

Opera Browser for Android

Research Opera Browser for Android Share May 21st, 2021 In this episode of theOpera Bug Bounty series, we introduce Opera for Android, our main product for the Android platform. What is Opera for Android Opera for Android is a Chromium-based browser that prides itself on a user-friendly and good...

Security changes and features of Opera 18

News Security changes and features of Opera 18 Share December 4th, 2013 Opera 18 is now out on the stable channel, so we wanted to take a moment to go through some of the new features from a security perspective. Media Access One of the new features is media access. That is; camera and microphone...

Cookies can be set for a top-level domain – Opera Security Advisories

Browsers should only allow cookies to be set for the website that created them. In some specific cases, Opera does not apply this restriction correctly, and allows a website to set a cookie for its entire top-level domain such as .com or .co.uk. A malicious site could then redirect the user to...

File inputs can disclose the path to selected files

When a file is selected in a file upload input, the path to that file is not exposed through the input's value property. This is done to protect any sensitive information which may be contained in the directory names. When manipulated by DOM this information should also not be exposed. Certain DO...

*.com accepted as wildcard match in SSL/TLS name matching

Certificate authorities are expected to vet all certificate registrations, but may fail to prevent fraudulent or erroneous registrations. Certificates which use a wild card immediately before the top level domain, or nulls in the domain name, may pass validation checks in Opera. Sites using such...

Malformed bitmaps can reveal old data from random places in memory

Specially malformed bitmap images can cause Opera to render the image using a palette made up from uninitialized memory. Using canvas, the pattern can be read and analyzed by JavaScript, so an attacker can get random samples of the user's memory, which may contain data...

History Search can reveal browsing history

Certain constructs are not escaped correctly by Opera's History Search results. These can be used to inject scripts into the page, which can then be used to look through the user's browsing history, including the contents of the pages they have visited. These may contain sensitive information...

History Search can be used to execute arbitrary code

When certain parameters are passed to Opera's History Search, they can cause content not to be correctly sanitized. This can allow scripts to be injected into the History Search results page. Such scripts can then run with elevated privileges and interact with Opera's configuration, allowing them...

data: URLs can spoof trusted trusted sites – Opera Security Advisories

data: URLs can spoof trusted trusted sites – Opera Security Advisories OPCOM Team | July 19, 2007 Summary Opera displays certain data: URLs wrongly, enabling URL spoofing. Severity: Moderately severe Problem description data: URLs embed data inside them, instead of linking to an externalresource...

The createPattern function can reveal old data from random places in memory – Opera Security Advisories

The createPattern function can reveal old data from random places in memory – Opera Security Advisories OPCOM Team | July 19, 2007 Summary The createPattern function can reveal old data from random places in memory Severity: moderately severe Problem description Opera for Linux, FreeBSD, and...

Opera may execute command line embedded in URLs – Opera Security Advisories

Opera may execute command line embedded in URLs – Opera Security Advisories OPCOM Team | November 23, 2005 Summary Opera will execute command lines embedded in the URL when anotherprogram uses Opera to open a link. This affects UNIX versions ofOpera Linux/FreeBSD/Solaris. Severity: High Problem...

Internationalized domain names (IDN) can be used for spoofing. – Opera Security Advisories

Internationalized domain names IDN can be used for spoofing. – Opera Security Advisories OPCOM Team | February 25, 2005 Summary Opera supports internationalized domain names IDN, which allowsfor example Russian or Chinese domain names to be written in theirown native scripts. However, this also...

GameMaker security update: Patch now to prevent DoS attacks

Security GameMaker security update: Patch now to prevent DoS attacks Share October 30th, 2025 Today we’re looking at a vulnerability discovered in GameMaker, the game development tool that streamlines and simplifies game dev for all users, regardless of skill level. The vulnerability in question...

Does the TunnelVision vulnerability affect Opera’s free VPN?

Privacy Does the TunnelVision vulnerability affect Opera’s free VPN? Share June 12th, 2024 Hello! You may have heard recently about a new type of vulnerability called TunnelVision that makes it possible for a malicious actor to bypass VPN protection. So you will be happy to know that Opera’s free...

Update your browser: Security fixes for latest Chrome zero-day

News, Security Update your browser: Security fixes for latest Chrome zero-day Share December 22nd, 2023 Hi everyone! The latest patches to the Opera, Opera GX, Opera Crypto, and Opera for Android browsers address several recent vulnerabilities, including a zero-day exploit CVE-2023-7024. We...

New Opera 93 Stable update includes fix for latest Chromium zero-day

Security New Opera 93 Stable update includes fix for latest Chromium zero-day Share December 2nd, 2022 Hi everyone! Opera for Windows and Mac have received Stable updates 93.0.4585.37 and 93.0.4585.39 respectively. Among other things, these updates include Chromium update 107.0.5304.122, which...

Earn up to $10K from the Opera Bug Bounty program

Security Earn up to $10K from the Opera Bug Bounty program Share April 30th, 2021 Join the Opera Bug Bounty program, find vulnerabilities in scope, tell us how you did it, and collect rewards. We pay up to $10K for confirmed high-value submissions. Opera has two bug bounty programs operated by...

To VPN or not to VPN?

Security To VPN or not to VPN? Share October 29th, 2020 Alice and Bob use VPN to fight Mallory, an inquisitive sysadmin. TL;DR: skip to the conclusions to see what Alice learned. The Privacy Problem Alice and Bob recently met Mallory, who works at the cable company providing internet access to th...

Unjam the logjam

Security Unjam the logjam Share June 9th, 2015 When a browser and website communicate over a secure connection, they encrypt and decrypt the data using a shared symmetric encryption key; the same key is used for encryption and decryption. In order for the browser and server to make sure they use...

Replaced code signing certificate – Opera Security Advisories

Opera Software recently experienced an attack on the internal infrastructure. Following best practices, Opera Software is replacing signing certificates in Opera with newly issued certificates. Certificates in Opera include the code signing certificate for desktop binaries and the signing...

CORS requests can omit the preflight request – Opera Security Advisories

Cross-Origin Resource Sharing CORS requests are required to send a preflight request if custom headers are included, to check that the host wishes to allow the full request to be made. An example of where this may be needed is for sites that use a custom header with a static value as part of thei...

Overlapping content can trick users into executing downloads – Opera Security Advisories

Dialogs such as the download dialog are usually displayed on top of page content, to ensure that the user knows that the dialog is requesting attention. In some cases, this policy was not implemented correctly in Opera, allowing certain page content to overlay the dialog. In these cases, clicking...

Opera may be used as a vector for multiple font issues in the underlying operating system – Opera Security Advisories

Opera may be used as a vector for multiple font issues in the underlying operating system – Opera Security Advisories OPCOM Team | December 17, 2010 Affected versions This vulnerability may be targeted through Opera for Windows. Severity Critical Description A flaw in the font handling on the...

Unexpected changes in tab focus can be used to run programs from the Internet

Tabs may be used to obscure a download dialog that is visible in another tab. The dialog will allow the user to choose to run downloaded executables directly. If the tab is closed or hidden at the moment that a user was about to click, they can end up clicking on the buttons in the dialog, causin...

Widget properties exposed to third party domains

In some cases, widget properties could be exposed to third party domains, leading to the possibility of leak of widget information, or configuration options for the widget...

Cross-domain data theft with CSS load

CSS can be loaded cross-domain, and in some cases it is be possible to read the data pointed to, leading to the possibility of cross-domain data theft...

Specially crafted JPEG images can be used to execute arbitrary code

Specially crafted JPEG images can cause Opera to corrupt memory and crash. Successful exploitation can lead to execution of arbitrary code...

TLS certificates can be used to execute arbitrary code – Opera Security Advisories

TLS certificates can be used to execute arbitrary code – Opera Security Advisories OPCOM Team | February 13, 2009 Severity Highly Severe Problem Description When connecting to a TLS-protected website, Opera parses the X.509 certificate. If a site uses a specially crafted Subject Alternative Name ...

Feed subscription can cause the wrong page address to be displayed

It has been reported that when a user subscribes to a news feed using the feed subscription button, the page address can be changed. This causes the address field not to update correctly. Although this can mean that that misleading information can be displayed in the address field, it can only...

Feed subscription can cause the wrong page address to be displayed – Opera Security Advisories

Feed subscription can cause the wrong page address to be displayed – Opera Security Advisories OPCOM Team | December 16, 2008 Severity Not Severe Problem Description It has been reported that when a user subscribes to a news feed using the feed subscription button, the page address can be changed...

The links panel can allow cross-site scripting

The links panel shows links in all frames on the current page, including links with JavaScript URLs. When a page is held in a frame, the script is incorrectly executed on the outermost page, not the page where the URL was located. This can be used to execute scripts in the context of an unrelated...

Startup crash can allow execution of arbitrary code

When Opera is registered as a handler for a given protocol, it can be started by external applications. In some cases, being started in this way can cause Opera to crash. To inject code, additional techniques will have to be employed...

Startup crash can allow execution of arbitrary code – Opera Security Advisories

Startup crash can allow execution of arbitrary code – Opera Security Advisories OPCOM Team | December 16, 2008 Severity Extremely Severe Problem Description When Opera is registered as a handler for a given protocol, it can be started by external applications. In some cases, being started in this...

Resized canvas patterns can cause Opera to execute arbitrary code

HTML CANVAS elements can use scaled images as patterns. With suitable scaling manipulation of the image, a script can cause Opera to crash. This crash can sometimes cause memory corruption. To inject code, additional techniques will have to be employed...

Representation of DOM attribute values could allow cross-site scripting – Opera Security Advisories

Representation of DOM attribute values could allow cross-site scripting – Opera Security Advisories OPCOM Team | December 16, 2008 Severity Moderately Severe Problem Description When XML is imported into a document, its attribute values are not correctly presented to the DOM. This can allow their...

Image properties can be used to execute scripts – Opera Security Advisories

Image properties can be used to execute scripts – Opera Security Advisories OPCOM Team | December 16, 2008 Severity Highly Severe Problem Description Image properties can contain custom comments. When displaying the image properties, Opera can be tricked into treating the comments as script. This...

a specially crafted JavaScript can make Opera execute arbitrary code

A virtual function call on an invalid pointer that may referencedata crafted by the attacker can be used to execute arbitrary code...