Users can be tricked into uploading unexpected files

Plug-ins may be used to seed the system clipboard with paths to a target file, while the user may not expect that to be the contents of the clipboard. If the user can be convinced to focus a file input and paste the contents of the clipboard, the file can then be immediately uploaded without...

Data URIs can be used to allow cross-site scripting

Data URIs are allowed to run scripts that manipulate pages from the site that directly opened them. In some cases, the opening site is not correctly detected. In these cases, Data URIs may erroneously be able to run scripts so that they interact with sites that did not directly cause them to be...

Multiple asynchronous document modifications can be used to execute arbitrary code

Multiple asynchronous calls to a script that modifies the document contents can cause Opera to reference an uninitialized value, which may lead to a crash. To inject code, additional techniques will have to be employed...

Registering Opera as a protocol handler can allow it to be used to execute arbitrary code

When an application attempts to access a URL that uses a protocol that it does not understand, it may choose to pass the URL to a registered handler for that protocol. If that registered handler is Opera, it will be started, passing the URL to open. Some external applications do not ensure that t...

A JPEG image with a malformed header can crash Opera

A specially crafted DHT marker in the JPEG file header can causea heap overflow. The malformed image alone will only cause a crash. To exploitthe flaw, the computer's memory must first be filled up withcode of the attacker's choice. This is not trivial to do reliably,so attempted attacks will oft...

(Updated) Specially crafted JPEG images enables the execution of arbitrary code. – Opera Security Advisories

Updated Specially crafted JPEG images enables the execution of arbitrary code. – Opera Security Advisories OPCOM Team | July 5, 2006 Summary A specially crafted JPEG image can enable the execution ofarbitrary code. Severity: Critical Affected versions: Versions prior to 9.0 of Opera forMicrosoft...

A very long title in a web page can cause a crash on startup

If a Windows user with Input Method Editor IME installedbookmarks a page with an extremely long element,Opera will crash upon next startup. Opera will not recoverfrom this on its own, so the user will not be able to startOpera.This affects Japanese users and others using IME for textinput. It als...

Error pages can be used to guess local file paths – Opera Security Advisories

Remote web pages should not be able to detect what files a user has on their local machine. Certain error pages do not apply this restriction correctly, allowing web pages to produce an error page where a script can run. The script can then use various events to detect whether files on the user’s...

Data URIs can be used to facilitate Cross-Site Scripting – Opera Security Advisories

Data URIs are only supposed to inherit the scripting origin from the site that creates them, such as by including them as the target of a link or an inline frame in the source of the document. Specific sequences of document and data URI loading can cause Opera to forget which document created the...

Double-clicking a link can unexpectedly run a program from the Internet – Opera Security Advisories

Double-clicking a link can unexpectedly run a program from the Internet – Opera Security Advisories OPCOM Team | June 29, 2010 Severity Moderately severe Description 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...

XSLT can be used to retrieve random contents of unrelated documents

XSLT is normally subject to strict controls, preventing documents from separate Web sites from reading the contents of other sites. Certain XSLT constructs can cause Opera to retrieve the wrong contents for the resulting document. These contents will appear randomly from the cached versions of an...

Error messages can leak onto unrelated sites

Scripting error messages are normally available only to the page that caused the error. In some cases, the error messages could be passed to other sites as the contents of unrelated variables, and may contain sensitive information. If those sites write the content into the page markup, this could...

Java applets can be used to read sensitive information

Once a Java applet has been cached, if a page can predict the cache path for that applet, it can load the applet from the cache, causing it to run in the context of the local machine. This allows it to read other cache files on the computer or perform other normally more restrictive actions. Thes...

Security fix: Addressing a low-impact Pinboards vulnerability

News, Security Security fix: Addressing a low-impact Pinboards vulnerability Share June 9th, 2026 Hi Opera users, Recently, an independent security researcher responsibly disclosed a vulnerability in Opera’s Pinboards feature, which helped our team to quickly work on a fix. The vulnerability...

Fuzzing HTTP Proxies: Privoxy, Part 3

Research Fuzzing HTTP Proxies: Privoxy, Part 3 Share January 4th, 2022 One of my earlier posts outlined how I had discovered six security vulnerabilities in the Privoxy software using the technique of fuzzing to cause the software to crash. This post outlines how I discovered three more...

Cross-domain JSON resources may be exposed as JavaScript variable data – Opera Security Advisories

JSON strings are sometimes exported by sites as a resource that cannot be read cross-domain, and may contain confidential data. The format of a JSON string ensures that it cannot be read as the contents of a variable, if it is included as a normal script. In some cases, Opera does not correctly...

Certain DOM manipulations can allow execution of arbitrary code – Opera Security Advisories

Certain DOM manipulations can allow execution of arbitrary code – Opera Security Advisories OPCOM Team | January 4, 2011 Severity High Description Various unexpected DOM manipulations can cause Opera to crash. In some cases, these crashes can occur in a way that allows execution of arbitrary code...

Private video streams can be intercepted

Video content may be used as filler content for a HTML5 canvas, if the video format is natively supported by Opera. If the video and page are from the same site, the content of the canvas can be safely read out by scripts. In some cases, Opera does not check the video's origin correctly, and may...

TLS protocol vulnerable to Man In The Middle attack – Opera Security Advisories

TLS protocol vulnerable to Man In The Middle attack – Opera Security Advisories OPCOM Team | June 29, 2010 Summary A vulnerability has been discovered in all current versions of the SSL and TLS protocols, that may allow an attacker to inject data and instructions into the HTTPS connection and tri...

TLS protocol vulnerable to Man In The Middle attack

A vulnerability has been discovered in all current versions of the SSL and TLS protocols, that may allow an attacker to inject data and instructions into the HTTPS connection and trick the server to believe the date and instructions came from the client.The attacker accomplishes this by first...

Users can be tricked into uploading unexpected files – Opera Security Advisories

Users can be tricked into uploading unexpected files – Opera Security Advisories OPCOM Team | June 29, 2010 Severity Less severe Description Plug-ins may be used to seed the system clipboard with paths to a target file, while the user may not expect that to be the contents of the clipboard. If th...

a specially crafted JavaScript can make Opera execute arbitrary code – Opera Security Advisories

a specially crafted JavaScript can make Opera execute arbitrary code – Opera Security Advisories OPCOM Team | August 7, 2007 A specially crafted JavaScript can make Opera execute arbitrary code. Severity: Highly severe Problem description A virtual function call on an invalid pointer that may...

Resolving the “screen capture” notification issue on MacOS Sonoma

News, Privacy Resolving the “screen capture” notification issue on MacOS Sonoma Share October 2nd, 2023 Hey everyone! We recently became aware of an issue that appears for some users of Sonoma, or MacOS 14 – the latest version of MacOS currently rolling out to Macs worldwide. It seems that upon...

Where to find Opera’s Privacy and Security team online

Security Where to find Opera’s Privacy and Security team online Share September 27th, 2023 Hello everyone! Through this blog, we strive to offer timely updates and important information about Opera and our products. This helps us maintain an open line of communication with our users, particularly...

Update your browser: Security updates address vulnerabilities including latest Chrome bugs

News, Security Update your browser: Security updates address vulnerabilities including latest Chrome bugs Share June 15th, 2023 Hi everyone! The Opera browser, Opera GX and Opera Crypto Browser have just received important updates addressing a number of vulnerabilities and bugs. Among those are t...

Address bar spoofing in Opera Touch for iOS – Opera Security Advisories

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...

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...

HTTP Content-Length header can be used to execute arbitrary code

Large values in the HTTP Content-Length header can cause Opera to crash. Certain specific values can cause a memory corruption, which in some cases can allow arbitrary code to be injected and executed. In most cases Opera will just crash. To inject code, additional techniques will have to be...

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...

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...

How Opera for Android’s revamped ad blocker improves your browsing experience

News, Privacy How Opera for Android’s revamped ad blocker improves your browsing experience Share December 11th, 2024 Hi Opera users! At Opera, we know how intrusive advertising can disrupt your browsing experience by turning it into a frustrating maze of pop-ups. That’s why we have included a...

Bug bounty open for Opera Android apps!

News Bug bounty open for Opera Android apps! Share November 20th, 2018 We are happy to announce that our applications are now covered by the Google Play Security Reward Program. Researchers are invited to help us improve the security of our chosen products in return for fame and up to $5,000!...

Specially crafted SVG images can allow execution of arbitrary code – Opera Security Advisories

Opera can display images created using the Scalable Vector Graphics SVG format. Specially crafted and malformed SVG images may cause Opera to crash when their documents are unloaded, and the crash may allow execution of malicious arbitrary code. To inject code, additional techniques will have to ...

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...

News feed preview can subscribe to feeds without interaction – Opera Security Advisories

News feed preview can subscribe to feeds without interaction – Opera Security Advisories OPCOM Team | August 12, 2010 Severity Low Description When Opera is previewing a news feed, certain types of content do not have their scripts removed correctly. These scripts are able to subscribe the user t...

File inputs can disclose the path to selected files – Opera Security Advisories

File inputs can disclose the path to selected files – Opera Security Advisories OPCOM Team | June 29, 2010 Severity Less severe Description 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 sensitiv...

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...

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...

Specially crafted addresses can execute arbitrary code – Opera Security Advisories

Specially crafted addresses can execute arbitrary code – Opera Security Advisories OPCOM Team | December 16, 2008 Severity Extremely Severe Problem Description If a malicious page redirects Opera to a specially crafted address URL, it can cause Opera to crash. Given sufficient address content, th...

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...

How does Opera make money? An explainer on monetization

Privacy How does Opera make money? An explainer on monetization Share June 22nd, 2026 Hi, Opera users! As many of you know, our products are free to download and use – so one of the most common questions we get from users is, “how does Opera make money?” It’s a fair question, and the answer is...

How we keep Opera users and products safe: Inside the role of Head of Security

Security How we keep Opera users and products safe: Inside the role of Head of Security Share May 8th, 2026 We usually think of security only when something goes wrong – whether it’s a suspicious login we noticed, a strange pop-up we got while browsing, or a headline we read about a data breach...

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...

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...

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...

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...

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...