Mozilla Firefox 4.x through 13.0, Firefox ESR 10.x before 10.0.6, Thunderbird 5.0 through 13.0, Thunderbird ESR 10.x before 10.0.6, and SeaMonkey before 2.11 do not properly handle duplicate values in X-Frame-Options headers, which makes it easier for remote attackers to conduct clickjacking attacks via a FRAME element referencing a web site that produces these duplicate values.

In Network Security Services (NSS) before 3.46, several cryptographic primitives had missing length checks. In cases where the application calling the library did not perform a sanity check on the inputs it could result in a crash due to a buffer overflow.

Bugzilla 2.x and 3.x before 3.4.14, 3.5.x and 3.6.x before 3.6.8, 3.7.x and 4.0.x before 4.0.4, and 4.1.x and 4.2.x before 4.2rc2 does not reject non-ASCII characters in e-mail addresses of new user accounts, which makes it easier for remote authenticated users to spoof other user accounts by choosing a similar e-mail address.

If the ALT and "a" keys are pressed when users receive an extension installation prompt, the extension will be installed without the install prompt delay that keeps the prompt visible in order for users to accept or decline the installation. A malicious web page could use this with spoofing on the page to trick users into installing a malicious extension. This vulnerability affects Firefox < 67.

Until explicitly accessed by script, window.globalThis is not enumerable and, as a result, is not visible to code such as Object.getOwnPropertyNames(window). Sites that deploy a sandboxing that depends on enumerating and freezing access to the window object may miss this, allowing their sandboxes to be bypassed. This vulnerability affects Firefox < 68.

Insufficient vetting of parameters passed with the Prompt:Open IPC message between child and parent processes can result in the non-sandboxed parent process opening web content chosen by a compromised child process. When combined with additional vulnerabilities this could result in executing arbitrary code on the user's computer. This vulnerability affects Firefox ESR < 60.7.2, Firefox < 67.0.4, and Thunderbird < 60.7.2.

Files with the .JNLP extension used for "Java web start" applications are not treated as executable content for download prompts even though they can be executed if Java is installed on the local system. This could allow users to mistakenly launch an executable binary locally. This vulnerability affects Firefox < 67.

Necko can access a child on the wrong thread during UDP connections, resulting in a potentially exploitable crash in some instances. This vulnerability affects Firefox < 68.

Mozilla 1.9 M8 and earlier, Mozilla Firefox 2 before 2.0.0.15, SeaMonkey 1.1.5 and other versions before 1.1.10, Netscape 9.0, and other Mozilla-based web browsers, when a user accepts an SSL server certificate on the basis of the CN domain name in the DN field, regard the certificate as also accepted for all domain names in subjectAltName:dNSName fields, which makes it easier for remote attackers to trick a user into accepting an invalid certificate for a spoofed web site.

An issue was discovered in Bleach 2.1.x before 2.1.3. Attributes that have URI values weren't properly sanitized if the values contained character entities. Using character entities, it was possible to construct a URI value with a scheme that was not allowed that would slide through unsanitized.

The web console and JavaScript debugger do not sanitize all output that can be hyperlinked. Both will display "chrome:" links as active, clickable hyperlinks in their output. Web sites should not be able to directly link to internal chrome pages. Additionally, the JavaScript debugger will display "javascript:" links, which users could be tricked into clicking by malicious sites. This vulnerability affects Firefox < 60.

A spoofing vulnerability can occur when a malicious site with an extremely long domain name is opened in an Android Custom Tab (a browser panel inside another app) and the default browser is Firefox for Android. This could allow an attacker to spoof which page is actually loaded and in use. Note: this issue only affects Firefox for Android. Other versions and operating systems are unaffected. This vulnerability affects Firefox < 59.

It is possible to spoof the filename of an attachment and display an arbitrary attachment name. This could lead to a user opening a remote attachment which is a different file type than expected. This vulnerability affects Thunderbird ESR < 52.8 and Thunderbird < 52.8.

A shared worker created from a "data:" URL in one tab can be shared by another tab with a different origin, bypassing the same-origin policy. This vulnerability affects Firefox < 59.

If manipulated hyperlinked text with "chrome:" URL contained in it is dragged and dropped on the "home" icon, the home page can be reset to include a normally-unlinkable chrome page as one of the home page tabs. This vulnerability affects Firefox < 60.

The filename appearing in the "Downloads" panel improperly renders some Unicode characters, allowing for the file name to be spoofed. This can be used to obscure the file extension of potentially executable files from user view in the panel. Note: the dialog to open the file will show the full, correct filename and whether it is executable or not. This vulnerability affects Firefox < 60.

If cursor visibility is toggled by script using from 'none' to an image and back through script, the cursor will be rendered temporarily invisible within Firefox. Note: This vulnerability only affects OS X. Other operating systems are not affected. This vulnerability affects Firefox < 58.

Crafted message headers can cause a Thunderbird process to hang on receiving the message. This vulnerability affects Thunderbird ESR < 52.8 and Thunderbird < 52.8.

A vulnerability in the notifications Push API where notifications can be sent through service workers by web content without direct user interaction. This could be used to open new tabs in a denial of service (DOS) attack or to display unwanted content from arbitrary URLs to users. This vulnerability affects Firefox < 59.

A vulnerability can occur when capturing a media stream when the media source type is changed as the capture is occurring. This can result in stream data being cast to the wrong type causing a potentially exploitable crash. This vulnerability affects Thunderbird < 60, Firefox ESR < 60.1, Firefox ESR < 52.9, and Firefox < 61.

When scanning QR codes, Firefox for Android would have allowed navigation to some URLs that do not point to web content.<br>*This bug only affects Firefox for Android. Other operating systems are unaffected.*. This vulnerability affects Firefox < 96.

Low descenders on some Tibetan characters in several fonts on OS X are clipped when rendered in the addressbar. When used as part of an Internationalized Domain Name (IDN) this can be used for domain name spoofing attacks. Note: This attack only affects OS X operating systems. Other operating systems are unaffected. This vulnerability affects Firefox < 58.

A vulnerability where the JavaScript JIT compiler inlines Array.prototype.push with multiple arguments that results in the stack pointer being off by 8 bytes after a bailout. This leaks a memory address to the calling function which can be used as part of an exploit inside the sandboxed content process. This vulnerability affects Firefox ESR < 60.2.2 and Firefox < 62.0.3.

A potentially exploitable crash in TransportSecurityInfo used for SSL can be triggered by data stored in the local cache in the user profile directory. This issue is only exploitable in combination with another vulnerability allowing an attacker to write data into the local cache or from locally installed malware. This issue also triggers a non-exploitable startup crash for users switching between the Nightly and Release versions of Firefox if the same profile is used. This vulnerability affects Thunderbird < 60.2.1, Firefox ESR < 60.2.1, and Firefox < 62.0.2.

Some special resource URIs will cause a non-exploitable crash if loaded with optional parameters following a '?' in the parsed string. This could lead to denial of service (DOS) attacks. This vulnerability affects Firefox < 63.

The displayed addressbar URL can be spoofed on Firefox for Android using a javascript: URI in concert with JavaScript to insert text before the loaded domain name, scrolling the loaded domain out of view to the right. This can lead to user confusion. *This vulnerability only affects Firefox for Android < 62.*

Punycode format text will be displayed for entire qualified international domain names in some instances when a sub-domain triggers the punycode display instead of the primary domain being displayed in native script and the sub-domain only displaying as punycode. This could be used for limited spoofing attacks due to user confusion. This vulnerability affects Firefox < 57.

The destructor function for the "WindowsDllDetourPatcher" class can be re-purposed by malicious code in concert with another vulnerability to write arbitrary data to an attacker controlled location in memory. This can be used to bypass existing memory protections in this situation. Note: This attack only affects Windows operating systems. Other operating systems are not affected. This vulnerability affects Thunderbird < 52.3, Firefox ESR < 52.3, and Firefox < 55.

A spoofing vulnerability can occur when a page switches to fullscreen mode without user notification, allowing a fake address bar to be displayed. This allows an attacker to spoof which page is actually loaded and in use. Note: This attack only affects Firefox for Android. Other operating systems are not affected. This vulnerability affects Firefox < 56.

Default fonts on OS X display some Tibetan characters as whitespace. When used in the addressbar as part of an IDN this can be used for domain name spoofing attacks. Note: This attack only affects OS X operating systems. Other operating systems are unaffected. This vulnerability affects Firefox < 54, Firefox ESR < 52.2, and Thunderbird < 52.2.

File downloads encoded with "blob:" and "data:" URL elements bypassed normal file download checks though the Phishing and Malware Protection feature and its block lists of suspicious sites and files. This would allow malicious sites to lure users into downloading executables that would otherwise be detected as suspicious. This vulnerability affects Firefox < 56, Firefox ESR < 52.4, and Thunderbird < 52.4.

A mechanism that uses AppCache to hijack a URL in a domain using fallback by serving the files from a sub-path on the domain. This has been addressed by requiring fallback files be inside the manifest directory. This vulnerability affects Thunderbird < 52.3, Firefox ESR < 52.3, and Firefox < 55.

On Windows systems, the logger run by the Windows updater deletes the file "update.log" before it runs in order to write a new log of that name. The path to this file is supplied at the command line to the updater and could be used in concert with another local exploit to delete a different file named "update.log" instead of the one intended. Note: This attack only affects Windows operating systems. Other operating systems are not affected. This vulnerability affects Firefox < 55.

CRLF injection vulnerability in the Digest Authentication support for Mozilla Firefox before 2.0.0.8 and SeaMonkey before 1.1.5 allows remote attackers to conduct HTTP request splitting attacks via LF (%0a) bytes in the username attribute.

On pages containing an iframe, the "data:" protocol can be used to create a modal dialog through Javascript that will have an arbitrary domains as the dialog's location, spoofing of the origin of the modal dialog from the user view. Note: This attack only affects installations with e10 multiprocess turned off. Installations with e10s turned on do not support the modal dialog functionality. This vulnerability affects Firefox < 56.

The combined, single character, version of the letter 'i' with any of the potential accents in unicode, such as acute or grave, can be spoofed in the addressbar by the dotless version of 'i' followed by the same accent as a second character with most font sets. This allows for domain spoofing attacks because these combined domain names do not display as punycode. This vulnerability affects Firefox < 57.

Several fonts on OS X display some Tibetan and Arabic characters as whitespace. When used in the addressbar as part of an IDN this can be used for domain name spoofing attacks. Note: This attack only affects OS X operating systems. Other operating systems are unaffected. This vulnerability affects Firefox < 56, Firefox ESR < 52.4, and Thunderbird < 52.4.

WebExtensions could use popups and panels in the extension UI to load an "about:" privileged URL, violating security checks that disallow this behavior. This vulnerability affects Firefox < 56.

Characters from the "Canadian Syllabics" unicode block can be mixed with characters from other unicode blocks in the addressbar instead of being rendered as their raw "punycode" form, allowing for domain name spoofing attacks through character confusion. The current Unicode standard allows characters from "Aspirational Use Scripts" such as Canadian Syllabics to be mixed with Latin characters in the "moderately restrictive" IDN profile. We have changed Firefox behavior to match the upcoming Unicode version 10.0 which removes this category and treats them as "Limited Use Scripts.". This vulnerability affects Firefox < 54, Firefox ESR < 52.2, and Thunderbird < 52.2.

When entered directly, Reader Mode did not strip the username and password section of URLs displayed in the addressbar. This can be used for spoofing the domain of the current page. This vulnerability affects Firefox < 54.

If a long user name is used in a username/password combination in a site URL (such as " http://UserName:Password@example.com"), the resulting modal prompt will hang in a non-responsive state or crash, causing a denial of service. This vulnerability affects Firefox < 55.

SVG loaded through "<img>" tags can use "<meta>" tags within the SVG data to set cookies for that page. This vulnerability affects Firefox < 57.

Some Arabic and Indic vowel marker characters can be combined with Latin characters in a domain name to eclipse the non-Latin character with some font sets on the addressbar. The non-Latin character will not be visible to most viewers. This allows for domain spoofing attacks because these combined domain names do not display as punycode. This vulnerability affects Firefox < 57.

A possibly exploitable crash triggered during layout and manipulation of bidirectional unicode text in concert with CSS animations. This vulnerability affects Thunderbird < 52.1, Firefox ESR < 52.1, and Firefox < 53.

Malicious sites can display a spoofed addressbar on a page when the existing location bar on the new page is scrolled out of view if an HTML editable page element is user selected. Note: This attack only affects Firefox for Android. Other operating systems are not affected. This vulnerability affects Firefox < 53.

An attack can use a blob URL and script to spoof an arbitrary addressbar URL prefaced by "blob:" as the protocol, leading to user confusion and further spoofing attacks. This vulnerability affects Firefox < 52.

URLs containing certain unicode glyphs for alternative hyphens and quotes do not properly trigger punycode display, allowing for domain name spoofing attacks in the location bar. This vulnerability affects Thunderbird < 45.7, Firefox ESR < 45.7, and Firefox < 51.

Android intents can be used to launch Firefox for Android in reader mode with a user specified URL. This allows an attacker to spoof the contents of the addressbar as displayed to users. Note: This attack only affects Firefox for Android. Other operating systems are not affected. This vulnerability affects Firefox < 53.

A mechanism to spoof the Firefox for Android addressbar using a "javascript:" URI. On Firefox for Android, the base domain is parsed incorrectly, making the resulting location less visibly a spoofed site and showing an incorrect domain in appended notifications. This vulnerability affects Firefox < 53.