JavaScript can be injected into an exported bookmarks file by placing JavaScript code into user-supplied tags in saved bookmarks. If the resulting exported HTML file is later opened in a browser this JavaScript will be executed. This could be used in social engineering and self-cross-site-scripting (self-XSS) attacks if users were convinced to add malicious tags to bookmarks, export them, and then open the resulting file. This vulnerability affects Firefox < 57.

The X.509 certificate validation functionality in Mozilla Firefox 4.0.x through 4.0.1 does not properly implement single-session security exceptions, which might make it easier for user-assisted remote attackers to spoof an SSL server via an untrusted certificate that triggers potentially unwanted local caching of documents from that server.

CRLF injection vulnerability in chart.cgi in Bugzilla before 3.2.10, 3.4.x before 3.4.10, 3.6.x before 3.6.4, and 4.0.x before 4.0rc2 allows remote attackers to inject arbitrary HTTP headers and conduct HTTP response splitting attacks via the query string, a different vulnerability than CVE-2010-2761 and CVE-2010-4411.

The NS_SecurityCompareURIs function in netwerk/base/public/nsNetUtil.h in Mozilla Firefox before 3.5.16 and 3.6.x before 3.6.13, and SeaMonkey before 2.0.11, does not properly handle (1) about:neterror and (2) about:certerror pages, which allows remote attackers to spoof the location bar via a crafted web site.

Mozilla Firefox before 3.5.14 and 3.6.x before 3.6.11, Thunderbird before 3.0.9 and 3.1.x before 3.1.5, and SeaMonkey before 2.0.9 recognize a wildcard IP address in the subject's Common Name field of an X.509 certificate, which might allow man-in-the-middle attackers to spoof arbitrary SSL servers via a crafted certificate issued by a legitimate Certification Authority.

Visual truncation vulnerability in netwerk/dns/src/nsIDNService.cpp in Mozilla Firefox before 3.0.11 and SeaMonkey before 1.1.17 allows remote attackers to spoof the location bar via an IDN with invalid Unicode characters that are displayed as whitespace, as demonstrated by the \u115A through \u115E characters.

The startDocumentLoad function in browser/base/content/browser.js in Mozilla Firefox 3.5.x before 3.5.11 and 3.6.x before 3.6.7, and SeaMonkey before 2.0.6, does not properly implement the Same Origin Policy in certain circumstances related to the about:blank document and a document that is currently loading, which allows (1) remote web servers to conduct spoofing attacks via vectors involving a 204 (aka No Content) status code, and allows (2) remote attackers to conduct spoofing attacks via vectors involving a window.stop call.

intl/uconv/util/nsUnicodeDecodeHelper.cpp in Mozilla Firefox before 3.6.7 and Thunderbird before 3.1.1 inserts a U+FFFD sequence into text in certain circumstances involving undefined positions, which might make it easier for remote attackers to conduct cross-site scripting (XSS) attacks via crafted 8-bit text.

The XMLDocument::load function in Mozilla Firefox before 3.5.9 and 3.6.x before 3.6.2, Thunderbird before 3.0.4, and SeaMonkey before 2.0.4 does not perform the expected nsIContentPolicy checks during loading of content by XML documents, which allows attackers to bypass intended access restrictions via crafted content.

A mechanism where when a new tab is loaded through JavaScript events, if fullscreen mode is then entered, the addressbar will not be rendered. This would allow a malicious site to displayed a spoofed addressbar, showing the location of an arbitrary website instead of the one loaded. Note: this issue only affects Firefox for Android. Desktop Firefox is unaffected. This vulnerability affects Firefox < 54.

Mozilla Firefox 3.5.1 and SeaMonkey 1.1.17, and Flock 2.5.1, allow context-dependent attackers to spoof the address bar, via window.open with a relative URI, to show an arbitrary file: URL after a victim has visited any file: URL, as demonstrated by a visit to a file: document written by the attacker.

Mozilla Firefox before 3.0.9, Thunderbird, and SeaMonkey do not properly implement the Same Origin Policy for (1) XMLHttpRequest, involving a mismatch for a document's principal, and (2) XPCNativeWrapper.toString, involving an incorrect __proto__ scope, which allows remote attackers to conduct cross-site scripting (XSS) attacks and possibly other attacks via a crafted document.

Mozilla Firefox before 3.0.9 and SeaMonkey 1.1.17 do not block javascript: URIs in Refresh headers in HTTP responses, which allows remote attackers to conduct cross-site scripting (XSS) attacks via vectors related to (1) injecting a Refresh header or (2) specifying the content of a Refresh header. NOTE: it was later reported that Firefox 3.6 a1 pre and Mozilla 1.7.x and earlier are also affected.

The jar: URI implementation in Mozilla Firefox before 3.0.9, Thunderbird, and SeaMonkey does not follow the Content-Disposition header of the inner URI, which allows remote attackers to conduct cross-site scripting (XSS) attacks and possibly other attacks via an uploaded .jar file with a "Content-Disposition: attachment" designation.

A unicode RTL order character in the downloaded file name can be used to change the file's name during the download UI flow to change the file extension. This vulnerability affects Firefox for iOS < 28.

Firefox did not reset the address bar after the beforeunload dialog was shown if the user chose to remain on the page. This could have resulted in an incorrect URL being shown when used in conjunction with other unexpected browser behaviors. This vulnerability affects Firefox < 80.

When a link to an external protocol was clicked, a prompt was presented that allowed the user to choose what application to open it in. An attacker could induce that prompt to be associated with an origin they didn't control, resulting in a spoofing attack. This was fixed by changing external protocol prompts to be tab-modal while also ensuring they could not be incorrectly associated with a different origin. This vulnerability affects Firefox < 82.

When in an endless loop, a website specifying a custom cursor using CSS could make it look like the user is interacting with the user interface, when they are not. This could lead to a perceived broken state, especially when interactions with existing browser dialogs and warnings do not work. This vulnerability affects Firefox ESR < 78.1, Firefox < 79, and Thunderbird < 78.1.

By holding a reference to the eval() function from an about:blank window, a malicious webpage could have gained access to the InstallTrigger object which would allow them to prompt the user to install an extension. Combined with user confusion, this could result in an unintended or malicious extension being installed. This vulnerability affects Firefox < 80, Thunderbird < 78.2, Thunderbird < 68.12, Firefox ESR < 68.12, Firefox ESR < 78.2, and Firefox for Android < 80.

An iframe sandbox element with the allow-popups flag could be bypassed when using noopener links. This could have led to security issues for websites relying on sandbox configurations that allowed popups and hosted arbitrary content. This vulnerability affects Firefox ESR < 78.1, Firefox < 79, and Thunderbird < 78.1.

A rogue webpage could override the injected WKUserScript used by the download feature, this exploit could result in the user downloading an unintended file. This vulnerability affects Firefox for iOS < 28.

Given an installed malicious file picker application, an attacker was able to overwrite local files and thus overwrite Firefox settings (but not access the previous profile). *Note: This issue only affected Firefox for Android. Other operating systems are unaffected.*. This vulnerability affects Firefox ESR < 68.11.

Using object or embed tags, it was possible to frame other websites, even if they disallowed framing using the X-Frame-Options header. This vulnerability affects Thunderbird < 78 and Firefox < 78.0.2.

Mozilla Firefox 3.x before 3.0.5 and 2.x before 2.0.0.19, Thunderbird 2.x before 2.0.0.19, and SeaMonkey 1.x before 1.1.14 does not properly parse URLs with leading whitespace or control characters, which might allow remote attackers to misrepresent URLs and simplify phishing attacks.

Add-on updates failed to verify that the add-on ID inside the signed package matched the ID of the add-on being updated. An attacker who could perform a man-in-the-middle attack on the user's connection to the update server and defeat the certificate pinning protection could provide a malicious signed add-on instead of a valid update. This vulnerability affects Firefox ESR < 45.5 and Firefox < 50.

An issue where a "<select>" dropdown menu can be used to cover location bar content, resulting in potential spoofing attacks. This attack requires e10s to be enabled in order to function. This vulnerability affects Firefox < 50.

Mozilla Firefox before 48.0 on Android allows remote attackers to spoof the address bar via left-to-right characters in conjunction with a right-to-left character set.

A mechanism where disruption of the loading of a new web page can cause the previous page's favicon and SSL indicator to not be reset when the new page is loaded. Note: this issue only affects Firefox for Android. Desktop Firefox is unaffected. This vulnerability affects Firefox < 50.

Mozilla Firefox before 48.0 does not properly set the LINKABLE and URI_SAFE_FOR_UNTRUSTED_CONTENT flags of about: URLs that are used for error pages, which makes it easier for remote attackers to conduct spoofing attacks via a crafted URL, as demonstrated by misleading text after an about:neterror?d= substring.

Mozilla Firefox before 48.0 allows remote attackers to spoof the location bar via crafted characters in the media type of a data: URL.

Mozilla Firefox before 44.0 allows user-assisted remote attackers to spoof a trailing substring in the address bar by leveraging a user's paste of a (1) wyciwyg: URI or (2) resource: URI.

The Firefox Health Reports (aka FHR or about:healthreport) feature in Mozilla Firefox before 46.0 does not properly restrict the origin of events, which makes it easier for remote attackers to modify sharing preferences by leveraging access to the remote-report IFRAME element.

Mozilla Firefox 43.x mishandles attempts to connect to the Application Reputation service, which makes it easier for remote attackers to trigger an unintended download by leveraging the absence of reputation data.

Mozilla Firefox before 47.0 allows remote attackers to bypass the Same Origin Policy and modify the location.host property via an invalid data: URL.

Mozilla Firefox before 44.0 on Android does not ensure that HTTPS is used for a lightweight-theme installation, which allows man-in-the-middle attackers to replace a theme's images and colors by modifying the client-server data stream.

Mozilla Firefox before 46.0 allows remote attackers to bypass the Content Security Policy (CSP) protection mechanism via the multipart/x-mixed-replace content type.

Mozilla Firefox before 44.0 on Android allows remote attackers to spoof the address bar via the scrollTo method.

Mozilla Firefox before 47.0 allows remote attackers to spoof permission notifications via a crafted web site that rapidly triggers permission requests, as demonstrated by the microphone permission or the geolocation permission.

GUI overlay vulnerability in Mozilla Firefox before 2.0.0.13 and SeaMonkey before 1.1.9 allows remote attackers to spoof form elements and redirect user inputs via a borderless XUL pop-up window from a background tab.

When DNS over HTTPS is in use, it intentionally filters RFC1918 and related IP ranges from the responses as these do not make sense coming from a DoH resolver. However when an IPv4 address was mapped through IPv6, these addresses were erroneously let through, leading to a potential DNS Rebinding attack. This vulnerability affects Firefox < 83, Firefox ESR < 78.5, and Thunderbird < 78.5.

When invoking protocol handlers for external protocols, a supplied parameter URL containing spaces was not properly escaped. This vulnerability affects Thunderbird < 91.4.0, Firefox ESR < 91.4.0, and Firefox < 95.

It was possible to recreate previous cursor spoofing attacks against users with a zoomed native cursor. This vulnerability affects Thunderbird < 91.4.0, Firefox ESR < 91.4.0, and Firefox < 95.

WebExtensions with the correct permissions were able to create and install ServiceWorkers for third-party websites that would not have been uninstalled with the extension. This vulnerability affects Firefox < 95.