Hidden keyboard navigation can allow cross site scripting or code execution – Opera Security Advisories

When a user is interacting with a window, that window should be visible to the user, to ensure that the user realizes it is there. If a page is displayed in a small enough window, the user may not realize it is being displayed, and if the right keyboard sequence is carefully followed, they can en...

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...

Carefully timed reloads and redirects can spoof the address field – Opera Security Advisories

The address field should always show the address of the page that is being displayed. In certain cases, if a target site responds slowly, reloading an attacking page and redirecting to the target page can cause the address field to show the target site’s address, while the attacking site is still...

Changing from a single-user to a multi-user installation on Windows (rev2) – Opera Security Advisories

Changing from a single-user to a multi-user installation on Windows rev2 – Opera Security Advisories OPCOM Team | January 5, 2012 If you received the error message “There was a problem initializing Opera Mail. Engine Init Failed”, it may mean that you have a stand-alone USB installation of Opera...

Data URIs may be used to initiate cross site scripting against unrelated sites – Opera Security Advisories

Data URIs are supposed to inherit the security context from the page that created them. In some cases, Opera does not enforce this correctly, and will allow unrelated data URIs to interact both with each other, and their source pages. This can be used to enable cross site scripting against the...

HTTP header leakage when using Opera Turbo – Opera Security Advisories

HTTP header leakage when using Opera Turbo – Opera Security Advisories OPCOM Team | February 11, 2011 Severity High Description When using Opera Turbo, pages are requested by the Opera Turbo servers, sending the relevant HTTP headers for that request. In some cases, the headers are incorrectly...

Web pages can gain limited access to files on the user’s computer – Opera Security Advisories

Web pages can gain limited access to files on the user’s computer – Opera Security Advisories OPCOM Team | January 25, 2011 Severity High Description Certain types of HTTP responses and redirections can cause Opera to mistakenly give elevated privileges to remote web pages. These pages can then u...

Reloads and redirects can allow spoofing and cross site scripting – Opera Security Advisories

Reloads and redirects can allow spoofing and cross site scripting – Opera Security Advisories OPCOM Team | October 6, 2010 Severity Critical Description 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...

Malicious DLL files can be unintentionally loaded and allowed to run arbitrary code – Opera Security Advisories

Malicious DLL files can be unintentionally loaded and allowed to run arbitrary code – Opera Security Advisories OPCOM Team | September 8, 2010 Severity High Description Opera uses dynamic link libraries DLLs of its own, and several provided by the host operating system or plug-ins. In some cases,...

Data URIs can be used to allow cross-site scripting – Opera Security Advisories

Data URIs can be used to allow cross-site scripting – Opera Security Advisories OPCOM Team | June 22, 2010 Severity Highly severe Description 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...

Opera may be used as a vector for a font issue in the underlying operating system

A flaw in the font handling on the Windows operating system has been fixed by Microsoft. On unpatched systems, Web fonts may be used to exploit this issue through Opera...

Error messages can leak onto unrelated sites – Opera Security Advisories

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...

Web fonts can be used to spoof the page address – Opera Security Advisories

In some cases, a Web font intended to be used for page content could be incorrectly used by Opera to render parts of the user interface, including the address field. This can be used by a malicious site to display a false domain name in the address field...

Random number generator and input name linebreaks can be used to send custom data to other sites – Opera Security Advisories

Random number generator and input name linebreaks can be used to send custom data to other sites – Opera Security Advisories OPCOM Team | June 10, 2009 Severity Moderately severe Problem description Input names can contain line breaks when data is sent using POST. Suitable use of the random numbe...

History Search can reveal browsing history – Opera Security Advisories

History Search can reveal browsing history – Opera Security Advisories OPCOM Team | December 16, 2008 Severity Extremely Severe Platforms All desktop versions Problem Description Certain constructs are not escaped correctly by Opera’s History Search results. These can be used to inject scripts in...

Feed links can link to local files – Opera Security Advisories

Feed links can link to local files – Opera Security Advisories OPCOM Team | December 16, 2008 Severity Less Severe Problem Description As a security precaution, Opera does not allow Web pages to link to files on the user’s local disk. However, a flaw exists that allows Web pages to link to feed...

Insecure pages can show incorrect security information – Opera Security Advisories

Insecure pages can show incorrect security information – Opera Security Advisories OPCOM Team | December 16, 2008 Severity Less Severe Problem Description When insecure pages load content from secure sites into a frame, they can cause Opera to incorrectly report the insecure site as being secure...

Character Encoding Inheritance in iframes Can Enable Cross-Site Scripting – Opera Security Advisories

Character Encoding Inheritance in iframes Can Enable Cross-Site Scripting – Opera Security Advisories OPCOM Team | December 16, 2008 Severity Moderate Problem description Pages displayed inside an iframe will inherit the character encodingof the parent page, unless they specify their own characte...

Long hostnames in file: URLs can cause execution of arbitrary code

Exceptionally long host names in file: URLs can cause a buffer overflow, which may be exploited to execute arbitrary code. Remote Web pages cannot refer to file: URLs, so successful exploitation involves tricking users into manually opening the exploit URL, or a local file that refers to it...

Opera security advisory 2004-12-10 – Opera Security Advisories

Opera security advisory 2004-12-10 – Opera Security Advisories OPCOM Team | February 9, 2007 Opera security advisory Named frames or windows can be hi-jacked by malicious frames or windows. Periods in the file name and non-breaking spaces in the Content-Type header can make the save/open dialog...

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

A forged SSL server certificate can be accepted by Opera as a valid certificate – Opera Security Advisories OPCOM Team | September 21, 2006 Summary: A forged SSL server certificate can be accepted by Opera as a valid certificate. Severity: Highly critical Vulnerable versions: Opera for desktop...

Protected with Opera Neon: Understanding agentic browser security

Security Protected with Opera Neon: Understanding agentic browser security Share October 21st, 2025 Hi Opera users, If you were hanging out around these parts in the past few weeks, you might have noticed that we launched Opera Neon – an AI agentic browser that can browse with you or for you, tak...

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

News, Security Update your browser: Security fixes for latest Chrome zero-day Share August 23rd, 2024 Hi everyone! The latest patches to the Opera and Opera GX address several recent vulnerabilities, including a zero-day exploit CVE-2024-7971. We recommend updating your browsers to the latest...

Update your browser: Security fixes for latest Chrome bugs

News, Security Update your browser: Security fixes for latest Chrome bugs Share August 10th, 2023 Hi everyone! Opera, Opera GX, and Opera Crypto Browser have received important updates addressing a number of vulnerabilities and bugs. Among those are the following important vulnerabilities detecte...

Opera’s Security team at Barcelona Cybersecurity Congress 2023

Security Opera’s Security team at Barcelona Cybersecurity Congress 2023 Share February 9th, 2023 Hello readers! If you follow our Security team’s Twitter account it’s here, by the way!, you’ll have noticed we were busy last week meeting cybersecurity enthusiasts and professionals at this year’s...

It’s Data Privacy Day: Here’s how to protect your data and become your own privacy champion

News, Security It’s Data Privacy Day: Here’s how to protect your data and become your own privacy champion Share January 27th, 2023 Hello readers! January 28 is Data Privacy Day – an annual celebration of all things data protection and online privacy! It’s an opportunity for businesses and users ...

Opera’s Free Browser VPN Completes Independent Security Audit by Cure53

News Opera’s Free Browser VPN Completes Independent Security Audit by Cure53 Share March 30th, 2022 Today we’re happy to announce the completion of an independent security audit of Opera’s free built-in browser VPN. Opera’s free, no-log, built-in browser VPN was originally launched as part of the...

Opera becomes part of the CNA program

News Opera becomes part of the CNA program Share December 13th, 2019 Usually, Friday the 13th is considered to be an unlucky day. However, this is not the case for Opera, as we have great news, especially for security researchers and all security-minded Opera fans. We are proud to announce that...

Opera Privacy Statement Update 2019

Privacy Opera Privacy Statement Update 2019 Share February 7th, 2019 This is an outdated article. Please read Opera Privacy Statement Update 2022 instead. We have recently updated our end-user license agreements and our terms of service have been updated as well. We are also about to update our...

Opera asks for my keychain password on macOS – what do I do? Opera 53 has a new signing certificate

Security Opera asks for my keychain password on macOS – what do I do? Opera 53 has a new signing certificate Share May 30th, 2018 Hello, We would like to let you know that we have updated our software signing certificate from Opera Software ASA to Opera Software AS. This is why your macOS is aski...

Upcoming update with IDN homograph phishing fix

Security Upcoming update with IDN homograph phishing fix Share April 21st, 2017 Domains are an integral part of the internet. Similar to how people write different languages using different characters or scripts, domain names can be composed of various scripts in whole or in part, and are called...

DLL hijacking and the Opera browser

Security DLL hijacking and the Opera browser Share March 10th, 2017 Recently, a collection of documents was released online, which was claimed to have originated with a major World power. The documents listed hacking vectors that could be used to inject code into major operating systems and...

Legacy Opera Presto source code appearance in online sharing sites

Security Legacy Opera Presto source code appearance in online sharing sites Share January 18th, 2017 Opera recently became aware that source code from our legacy browser engine, Presto, has appeared in some online code and file sharing sites. This code is the property of Opera Software and has be...

Dealing with FREAK and SuperFish

Security Dealing with FREAK and SuperFish Share March 10th, 2015 The FREAK TLS attack Following the trend of memorable names for TLS attacks, FREAK was recently announced. This exploits a bug in some TLS libraries, combined with the support of ancient weak ciphers, to enable a MitM to force...

Security changes in Opera 25; the poodle attacks

Security Security changes in Opera 25; the poodle attacks Share October 15th, 2014 So the last weeks have been rather hectic behind the scenes in the browser security world, when Google security group found a new way to exploit a rather well known design weakness in SSLv3 published in the paper...

Possibly Tricking Users – The Perils of Drag n Drop Decadence

Security Possibly Tricking Users – The Perils of Drag n Drop Decadence Share May 12th, 2014 In the recent Opera 21 Stable release, we fixed a number of bugs relating to the address field. Normally, we would not want to give away too much about a security issue, as it would give a potential attack...

Private data can be disclosed to other computer users, or be modified by them – Opera Security Advisories

Private data such as cache, password files, and Opera’s configuration files are supposed to be visible only to the user who owns the Opera profile. Opera does not set the profile folder permissions correctly, allowing other computer users to read the sensitive contents of profile files. In some...

Malformed GIF images could allow execution of arbitrary code – Opera Security Advisories

When loading GIF images into memory, Opera should allocate the correct amount of memory to store that image. Specially crafted image files can cause Opera to allocate the wrong amount of memory. Subsequent data may then overwrite unrelated memory with attacker-controlled data. This can lead to a...

Truncated dialogs may be used to trick users – Opera Security Advisories

When an important dialog is being displayed, such as a download dialog, the entire dialog should be visible, so that the user can clearly see what the dialog’s buttons will do. In some cases, specific user interactions can cause Opera not to enforce this correctly, allowing the window to become...

Element HTML content can be incorrectly returned without escaping, bypassing some HTML sanitizers – Opera Security Advisories

When sites accept HTML from untrusted users, and use that HTML as page content, they typically sanitize the untrusted HTML to ensure that it does not contain any harmful content, such as malicious scripts. In some cases, this sanitization may be performed by writing and reading the contents of DO...

Certain URL constructs can allow arbitrary code execution – Opera Security Advisories

Certain page address URL constructs can cause Opera to allocate the wrong amount of memory for storing the address. When it then attempts to store the address, it will overwrite unrelated memory with attacker-controlled data. This can lead to a crash, which may also execute that data as code...

Small windows can be used in several ways to trick users into executing downloads – Opera Security Advisories

When the download dialog is displayed, it should always be visible to the user, to ensure that the user realizes it is there. If the dialog is displayed in a small enough window, the user may not realize it is being displayed, and if the right keyboard sequence is carefully followed, they can end...

Web page content may overlap the address field – Opera Security Advisories

The browser’s user interface contains several pieces of security information. To preserve this information correctly, web page content should not be able to display over the user interface. Certain styling can cause Opera to allow the content to be displayed outside the page, over the address...

Clickjacking attacks may be carried out against internal opera: URLs – Opera Security Advisories

Clickjacking attacks may be carried out against internal opera: URLs – Opera Security Advisories OPCOM Team | January 25, 2011 Severity High Description Internal opera: URLs which may be used to modify the Opera configuration have some intentional restrictions that are designed to mitigate possib...

Unrestricted File I/O can be used by Widgets to execute arbitrary code – Opera Security Advisories

Unrestricted File I/O can be used by Widgets to execute arbitrary code – Opera Security Advisories OPCOM Team | June 29, 2010 Severity Highly severe Description Widgets may use File I/O to create, read, modify, or delete files, with the user’s permission. When using this functionality, Opera shou...

Specially crafted JPEG images can be used to execute arbitrary code – Opera Security Advisories

Specially crafted JPEG images can be used to execute arbitrary code – Opera Security Advisories OPCOM Team | February 25, 2009 Severity Extremely Severe Problem Description Specially crafted JPEG images can cause Opera to corrupt memory and crash. Successful exploitation can lead to execution of...

Feed preview can reveal contents of unrelated news feeds – Opera Security Advisories

Feed preview can reveal contents of unrelated news feeds – Opera Security Advisories OPCOM Team | December 16, 2008 Severity Highly Severe Platforms All desktop versions Problem Description When Opera is previewing a news feed, some scripts are not correctly blocked. These scripts are able to...

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...

Malformed bitmaps can reveal old data from random places in memory – Opera Security Advisories

Malformed bitmaps can reveal old data from random places in memory – Opera Security Advisories OPCOM Team | December 16, 2008 Severity Moderately Severe Problem Description Specially malformed bitmap images can cause Opera to render the image using a palette made up from uninitialized memory. Usi...

Sites can change framed content on other sites – Opera Security Advisories

Sites can change framed content on other sites – Opera Security Advisories OPCOM Team | December 16, 2008 Severity Highly Severe Problem Description Scripts are able to change the addresses of framed pages that come from the same site. Due to a flaw in the way that Opera checks what frames can be...