Heap buffer overflow in string to number conversion

Passing very long strings through the string to number conversion using JavaScript in Opera may result in heap buffer overflows. This also affects the dtoa routine, and was reported in CVE-2009-0689. In most cases Opera will just freeze or terminate, but in some cases this could lead to a crash...

Opera security upgrade for Mac OS X

Opera 9.24 has a highly recommended security upgrade for users of the Adobe Flash Player 9.0.47.0 and earlier on Mac OS X. A security issue in Adobe Flash Player 9.0.47.0 and earlier running in Opera on Mac OS X has been found. Details about the vulnerability will be disclosed at a later date...

Vulnerability in createSVGTransformFromMatrix (JavaScript, SVG)

Passing an incorrect object to createSVGTransformFromMatrixcan crash Opera and enable arbitrary code execution. Users who have disabled JavaScript are not affected...

Update your browser: Security fix for Chrome zero-day CVE-2026-2441

News, Security Update your browser: Security fix for Chrome zero-day CVE-2026-2441 Share February 16th, 2026 Hi everyone! The latest patches to Opera, Opera GX, Opera Air, Opera Neon, and Opera for Android address several recent vulnerabilities, including a zero-day exploit CVE-2026-2441. We...

Manipulating the window can be used to spoof the page address

Web page scripts can be used to alter the size of the browser window. In some cases, this manipulation can cause the wrong part of the Web page address to be displayed in the Address Bar, so that the part that is initially visible to the user is not the start of the address, and may contain conte...

Data URLs with executables and misleading download dialog

The data URL scheme allows authors to embed binary files,instead of using links to external files. Data URLscontaining file types that Opera can display are renderedinline; other file types will be handled by Opera'sdownload dialog. A bug in Opera's file download handling causes the downloaddialo...

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

Input names can contain line breaks when data is sent using POST. Suitable use of the random number generator can reveal predictable boundaries that will be used when sending the POST data. These can be combined to add extra boundaries into the data, containing payloads that may confuse the...

Sites can change framed content on other sites

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 changed, a site can change the address of frames on other sites inside any window that it has opened. This allows sites to open pages from other...

Cross-domain checks may be bypassed, allowing limited data theft using CSS

CSS can be loaded cross-domain. In some cases, files that do not contain CSS may be partially interpreted as CSS. It is possible to make Opera incorrectly treat remote CSS files as if they were CSS files from the document-origin server, allowing the interpreted parts of a remote file to be read b...

Certain characters may be used for domain name spoofing

Opera uses several approaches to prevent spoofing of internationalized domain names IDN with characters that look similar to each other. With untrusted top-level domains, Opera prevents certain combinations of characters from being used in the same part of a domain name as each other, and should...

Web fonts can be used to spoof the page address

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...

Update your browser: Security fix for Chrome zero-days CVE 2026-3909 & CVE-2026-3910

News, Security Update your browser: Security fix for Chrome zero-days CVE 2026-3909 & CVE-2026-3910 Share March 14th, 2026 Hi everyone! The latest patches to Opera’s browsers address several recent vulnerabilities, including two zero-day exploits CVE 2026-3909 and CVE-2026-3910. We recommend...

Phishing attack possible with a delayed JavaScript prompt

A malicious page can be crafted to send the userto his banking site, and shortly afterwardsdisplay a dialog enticing the user to type inhis bank login credentials.The dialog will appear in front of the bankingpage, while the window it really belongs to willbe hidden. If the timing and context is...

Malformed JPEG headers can be used to execute arbitrary code

A specially crafted JPEG header can cause Opera to crash, allowing execution of arbitrary code...

A very large href attribute value in HTML can crash Opera

A Web page containing a very large href attribute value cancause Opera to crash.This exploit causes Opera to access the wrong location inmemory, so Opera is forced to quit. It is not possibleexploit this to run arbitrary code...

Specially crafted Java applets can crash Opera

Java code using LiveConnect methods to remove a property of aJavaScript object may in some cases use null pointers that canmake Opera crash. This crash is not exploitable and such code israre on the web...

Built-in XSLT templates can allow cross-site scripting

Built-in XSLT templates incorrectly handle escaped content and can cause it to be treated as markup. If a site accepts content from untrusted users, which it then displays using XSLT as escaped strings, this can allow scripted markup to be injected. The scripts will then be executed in the securi...

Script injection in feed preview can reveal contents of unrelated news feeds

When Opera is previewing a news feed, some scripted URLs are not correctly blocked. These can execute scripts which are able to subscribe the user to any feed URL that the attacker chooses, and can also view the contents of any feeds that the user is subscribed to. These may contain sensitive...

Opera may show some incorrect characters in the address bar

Some Unicode characters are treated incorrectly, which might cause international domain names that use them to be shown in the wrong format. Showing these addresses in Unicode instead of punycode could allow for limited address spoofing...

MD2 algorithm used by security certificates is considered weak

Digital signatures made with the MD2 algorithm are used in some of the issuer certificates that Opera trusts. MD2 is now considered weak...

Custom shortcuts can pass the wrong parameters to applications

Custom shortcut and menu commands can be used to activate external applications. In some cases, the parameters passed to these applications are not prepared correctly, and may be created from uninitialized memory. These may be misinterpreted as additional parameters, and depending on the...

Manipulating text input contents can allow execution of arbitrary code

Manipulating certain text-area contents can cause a buffer overflow, which may be exploited to execute arbitrary code...

The createPattern function can reveal old data from random places in memory

Opera for Linux, FreeBSD, and Solaris has a flaw in the createPattern function thatleaves old data that was in the memory before Opera allocated itin the new pattern. The pattern can be read and analyzed byJavaScript, so an attacker can get random samples of the user'smemory, which may contain da...

(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...

Unrestricted File I/O can be used by Widgets to execute arbitrary code

Widgets may use File I/O to create, read, modify, or delete files, with the user's permission. When using this functionality, Opera should request permission from the user, and ask for a location to use for the files that will be manipulated. In some cases, Opera fails to ask for permission, and...

Fast Forward can allow cross-site scripting

If a link that uses a JavaScript URL triggers Opera's Fast Forward feature, when the user activates Fast Forward, the script should run on the current page. 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 b...

Pages held in frames are able to change the location of pages in unrelated frames on the parent page

Pages from different sources held on the same parent page should not be able to modify the locations of each other. In affected Opera versions, if a page contains frames from both a trusted but not secured, and an untrusted source, the untrusted page is able to replace the contents of a named...

Malicious torrent files can execute arbitrary code in Opera

A specially crafted torrent file can cause a buffer overflow in Opera.This allows arbitrary code to be injected and executed. The overflow happens when the user right-clicks on the torrent entryin the transfer manager. Simply clicking on the torrent link willnot trigger this flaw...

The link tooltip and the statusbar can be misleading

It is possible to make a form input that looks like an image link.If the form input has a "title" attribute, the status bar will showthe "title". A "title" which looks like a URL can mislead the user,since the title can say http://nice.familiar.com/, while the formaction can be something...

Protecting your privacy: Opera has completed an independent no-log audit of its free browser VPN

Privacy Protecting your privacy: Opera has completed an independent no-log audit of its free browser VPN Share September 25th, 2024 Hi Opera users! We are excited to announce that we have successfully completed an independent audit of our no-log policy for Opera’s free browser VPN available on...

News feed preview can subscribe to feeds without interaction

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 to the feed without their consent...

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...

Rich editing allows cross domain scripting – Opera Security Advisories

Rich editing allows cross domain scripting – Opera Security Advisories OPCOM Team | December 16, 2008 Problem Description Rich editing using designMode allows page contents to be edited. Pages can use this ability to inject scripts into pages from other domains. This allows cross domain scripting...

Insecure pages can show incorrect security information

When insecure pages load content from secure sites into a frame, they can cause Opera to incorrectly report the insecure site as being secure. The padlock icon will incorrectly be shown, and the security information dialog will state that the connection is secure, but without any certificate...

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...

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...

HTML parsing flaw can cause Opera to execute arbitrary code

Certain HTML constructs can cause the resulting DOM to change unexpectedly, which triggers a crash. To inject code, additional techniques will have to be employed...

Certain characters can obscure the page address

When a page address contains certain characters, they can cause the page address text to be misplaced. In some cases, this could make characters be indistinguishable from each other, allowing some site addresses to look like other site addresses...

Security fix: Addressing a GX mods vulnerability

News, Security Security fix: Addressing a GX mods vulnerability Share July 3rd, 2026 Hi Opera users, Recently, an independent security researcher responsibly disclosed a vulnerability in Opera GX. The vulnerability, which has since been patched, took advantage of our mods functionality. After...

Here’s how Opera’s Paste Protect guards you natively against clipboard attacks

News, Security Here’s how Opera’s Paste Protect guards you natively against clipboard attacks Share July 2nd, 2026 At Opera, user security is a top priority. That’s why today, we are excited to announce that Opera is the first browser to introduce Paste Protect: a native defense measure against...

Update your browser: Security fix for Chrome zero-day CVE-2026-11645

News, Security Update your browser: Security fix for Chrome zero-day CVE-2026-11645 Share June 11th, 2026 Hi everyone! The latest patches to Opera’s browsers address several recent vulnerabilities, including a zero-day exploit CVE-2026-11645. We recommend updating your browsers to the latest...

Busting VPN myths: What a VPN can do for your privacy and what it can’t

Privacy Busting VPN myths: What a VPN can do for your privacy and what it can’t Share March 6th, 2026 If you’re reading this blog, you have probably heard of or used a VPN before. The truth is, VPNs are incredibly useful! They are one of the most effective tools for protecting your online privacy...

Debunking misinformation about Opera’s browsers

Privacy, Security Debunking misinformation about Opera’s browsers Share July 6th, 2023 At Opera, we take the privacy and security of our users very seriously. As a European company, we have to be compliant with the GDPR – one of the strongest, if not the strongest, data protection frameworks in t...

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...

Representation of DOM attribute values could allow cross-site scripting

When XML is imported into a document, its attribute values are not correctly presented to the DOM. This can allow their values to bypass sanitization filters. If these values are used as document content, they may in some cases allow scripts to be inserted...

Image properties can be used to execute scripts

Image properties can contain custom comments. When displaying the image properties, Opera can be tricked into treating the comments as script. This can cause the script to be run in the wrong security context...

canvas functions can reveal data from random places in memory

There is a flaw in the way that certain canvas functions are handled, that can cause the canvas to be painted with very small amounts of data constructed from random memory. The resulting canvas image can be read and analyzed by JavaScript, so an attacker can get random samples of the user's...

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...

Opera’s HTTP authentication cuts off long server names at the end – Opera Security Advisories

Opera’s HTTP authentication cuts off long server names at the end – Opera Security Advisories OPCOM Team | July 19, 2007 Summary Opera’s HTTP authentication dialog cuts off long server name at the right hand end. Severity: Less severe Problem description Opera’s HTTP authentication dialog is...