When a new protocol handler is registered, the API accepts a title argument which can be used to mislead users about which domain is registering the new protocol. This may result in the user approving a protocol handler that they otherwise would not have. This vulnerability affects Firefox < 63.

Mozilla Network Security Services (NSS) before 3.19, as used in Mozilla Firefox before 39.0, Firefox ESR 31.x before 31.8 and 38.x before 38.1, Thunderbird before 38.1, and other products, does not properly determine state transitions for the TLS state machine, which allows man-in-the-middle attackers to defeat cryptographic protection mechanisms by blocking messages, as demonstrated by removing a forward-secrecy property by blocking a ServerKeyExchange message, aka a "SMACK SKIP-TLS" issue.

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.

Cross-site scripting (XSS) vulnerability in Mozilla Firefox before 1.5.0.4 allows user-assisted remote attackers to inject arbitrary web script or HTML by tricking a user into (1) performing a "View Image" on a broken image in which the SRC attribute contains a Javascript URL, or (2) selecting "Show only this frame" on a frame whose SRC attribute contains a Javascript URL.

The Add-on SDK in Mozilla Firefox before 42.0 misinterprets a "script: false" panel setting, which makes it easier for remote attackers to conduct cross-site scripting (XSS) attacks via inline JavaScript code that is executed within a third-party extension.

Mozilla Network Security Services (NSS) before 3.20.2, as used in Mozilla Firefox before 43.0.2 and Firefox ESR 38.x before 38.5.2, does not reject MD5 signatures in Server Key Exchange messages in TLS 1.2 Handshake Protocol traffic, which makes it easier for man-in-the-middle attackers to spoof servers by triggering a collision.

When following a link that opened an intent://-schemed URL, causing a custom tab to be opened, Firefox for Android could be tricked into displaying the incorrect URI. <br> *Note: This issue only affects Firefox for Android. Other operating systems are unaffected.*. This vulnerability affects Firefox ESR < 68.7.

Mozilla Firefox before 42.0 on Android does not ensure that the address bar is restored upon fullscreen-mode exit, which allows remote attackers to spoof the address bar via crafted JavaScript code.

Cross-site scripting (XSS) vulnerability in Bugzilla before 2.18, including 2.16.x before 2.16.11, allows remote attackers to inject arbitrary HTML and web script via forced error messages, as demonstrated using the action parameter.

CRLF injection vulnerability in Mozilla Firefox before 2.0.0.12 allows remote user-assisted web sites to corrupt the user's password store via newlines that are not properly handled when the user saves a password.

Mozilla Firefox before 2.0.0.12 and SeaMonkey before 1.1.8 allows user-assisted remote attackers to trick the user into uploading arbitrary files via label tags that shift focus to a file input field, aka "focus spoofing."

When a malicious application installed on the user's device broadcast an Intent to Firefox for Android, arbitrary headers could have been specified, leading to attacks such as abusing ambient authority or session fixation. This was resolved by only allowing certain safe-listed headers. *Note: This issue only affected Firefox for Android. Other operating systems are unaffected.*. This vulnerability affects Firefox < 84.

Cross-origin iframes that contained a login form could have been recognized by the login autofill service, and populated. This could have been used in clickjacking attacks, as well as be read across partitions in dynamic first party isolation. This vulnerability affects Firefox < 83.

Mozilla Firefox before 2.0.0.10 and SeaMonkey before 1.1.7 sets the Referer header to the window or frame in which script is running, instead of the address of the content that initiated the script, which allows remote attackers to spoof HTTP Referer headers and bypass Referer-based CSRF protection schemes by setting window.location and using a modal alert dialog that causes the wrong Referer to be sent.

It was possible to cause the browser to enter fullscreen mode without displaying the security UI; thus making it possible to attempt a phishing attack or otherwise confuse the user. This vulnerability affects Firefox < 83, Firefox ESR < 78.5, and Thunderbird < 78.5.

OneCRL was non-functional in the new Firefox for Android due to a missing service initialization. This could result in a failure to enforce some certificate revocations. *Note: This issue only affected Firefox for Android. Other operating systems are unaffected.*. This vulnerability affects Firefox < 83.

When a HTTPS pages was embedded in a HTTP page, and there was a service worker registered for the former, the service worker could have intercepted the request for the secure page despite the iframe not being a secure context due to the (insecure) framing. This vulnerability affects Firefox < 84.

When accepting a malicious intent from other installed apps, Firefox for Android accepted manifests from arbitrary file paths and allowed declaring webapp manifests for other origins. This could be used to gain fullscreen access for UI spoofing and could also lead to cross-origin attacks on targeted websites. *Note: This issue only affected Firefox for Android. Other operating systems are unaffected.*. This vulnerability affects Firefox < 83.

A flaw in Mozilla's embedded certificate code might allow web sites to install root certificates on devices without user approval.

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 listening for page changes with a Mutation Observer, a malicious web page could confuse Firefox Screenshots into interacting with elements other than those that it injected into the page. This would lead to internal errors and unexpected behavior in the Screenshots code. This vulnerability affects Firefox < 83.

By attempting to connect a website using an unresponsive port, an attacker could have controlled the content of a tab while the URL bar displayed the original domain. *Note: This issue only affects Firefox for Android. Other operating systems are unaffected.*. This vulnerability affects Firefox < 84.

Mozilla Firefox before 2.0.0.8 and SeaMonkey before 1.1.5 can hide the window's titlebar when displaying XUL markup language documents, which makes it easier for remote attackers to conduct phishing and spoofing attacks by setting the hidechrome attribute.

Argument injection vulnerability in Mozilla Firefox before 2.0.0.5, when running on systems with Thunderbird 1.5 installed and certain URIs registered, allows remote attackers to conduct cross-browser scripting attacks and execute arbitrary commands via shell metacharacters in a mailto URI, which are inserted into the command line that is created when invoking Thunderbird.exe, a similar issue to CVE-2007-3670.

Mozilla Firefox 2.0.0.5, Thunderbird 2.0.0.5 and before 1.5.0.13, and SeaMonkey 1.1.3 allows remote attackers to conduct cross-site scripting (XSS) attacks with chrome privileges via an addon that inserts a (1) javascript: or (2) data: link into an about:blank document loaded by chrome via (a) the window.open function or (b) a content.location assignment, aka "Cross Context Scripting." NOTE: this issue is caused by a CVE-2007-3089 regression.

The focus handling for the onkeydown event in Mozilla Firefox 1.5.0.12, 2.0.0.4 and other versions before 2.0.0.8, and SeaMonkey before 1.1.5 allows remote attackers to change field focus and copy keystrokes via the "for" attribute in a label, which bypasses the focus prevention, as demonstrated by changing focus from a textarea to a file upload field.

Mozilla Firefox before 2.0.0.5 does not prevent use of document.write to replace an IFRAME (1) during the load stage or (2) in the case of an about:blank frame, which allows remote attackers to display arbitrary HTML or execute certain JavaScript code, as demonstrated by code that intercepts keystroke values from window.event, aka the "promiscuous IFRAME access bug," a related issue to CVE-2006-4568.

Mozilla Firefox 1.5.x before 1.5.0.12 and 2.x before 2.0.0.4, and SeaMonkey 1.0.9 and 1.1.2, allows remote attackers to spoof or hide the browser chrome, such as the location bar, by placing XUL popups outside of the browser's content pane. NOTE: this issue can be leveraged for phishing and other attacks.

Mozilla Firefox before 40.0 allows man-in-the-middle attackers to bypass a mixed-content protection mechanism via a feed: URL in a POST request.

A mechanism to spoof the addressbar through the user interaction on the addressbar and the "onblur" event. The event could be used by script to affect text display to make the loaded site appear to be different from the one actually loaded within the addressbar. This vulnerability affects Thunderbird < 52.1, Firefox ESR < 52.1, and Firefox < 53.

Cross-site scripting (XSS) vulnerability in Atom feeds in Bugzilla 2.20.3, 2.22.1, and 2.23.3, and earlier versions down to 2.20.1, allows remote attackers to inject arbitrary web script or HTML via unspecified vectors.

Mozilla Firefox might allow remote attackers to conduct spoofing and phishing attacks by writing to an about:blank tab and overlaying the location bar.

The TLS protocol 1.2 and earlier, when a DHE_EXPORT ciphersuite is enabled on a server but not on a client, does not properly convey a DHE_EXPORT choice, which allows man-in-the-middle attackers to conduct cipher-downgrade attacks by rewriting a ClientHello with DHE replaced by DHE_EXPORT and then rewriting a ServerHello with DHE_EXPORT replaced by DHE, aka the "Logjam" issue.

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.

Mozilla Firefox before 41.0 on Android allows user-assisted remote attackers to spoof address-bar attributes by leveraging lack of navigation after a paste of a URL with a nonstandard scheme, as demonstrated by spoofing an SSL attribute.

A vulnerability where a WebExtension can run content scripts in disallowed contexts following navigation or other events. This allows for potential privilege escalation by the WebExtension on sites where content scripts should not be run. This vulnerability affects Firefox ESR < 60.3 and Firefox < 63.

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 before 39.0, Firefox ESR 38.x before 38.1, and Thunderbird before 38.1 do not enforce key pinning upon encountering an X.509 certificate problem that generates a user dialog, which allows user-assisted man-in-the-middle attackers to bypass intended access restrictions by triggering a (1) expired certificate or (2) mismatched hostname for a domain with pinning enabled.

Mozilla Network Security Services (NSS) before 3.19.1, as used in Mozilla Firefox before 39.0, Firefox ESR 31.x before 31.8 and 38.x before 38.1, and other products, does not properly perform Elliptical Curve Cryptography (ECC) multiplications, which makes it easier for remote attackers to spoof ECDSA signatures via unspecified vectors.

By using the reflected URL in some special resource URIs, such as chrome:, it is possible to inject stylesheets and bypass Content Security Policy (CSP). This vulnerability affects Firefox < 63.

Mozilla Firefox 2.0 before 2.0.0.1 allows remote attackers to bypass Cross-Site Scripting (XSS) protection via vectors related to a Function.prototype regression error.

Mozilla Firefox before 37.0 on OS X does not ensure that the cursor is visible, which allows remote attackers to conduct clickjacking attacks via a Flash object in conjunction with DIV elements associated with layered presentation, and crafted JavaScript code that interacts with an IMG element.

Mozilla Firefox before 37.0 does not require an HTTPS session for lightweight theme add-on installations, which allows man-in-the-middle attackers to bypass an intended user-confirmation requirement by deploying a crafted web site and conducting a DNS spoofing attack against a mozilla.org subdomain.

The HTTP Alternative Services feature in Mozilla Firefox before 37.0.1 allows man-in-the-middle attackers to bypass an intended X.509 certificate-verification step for an SSL server by specifying that server in the uri-host field of an Alt-Svc HTTP/2 response header.

The UITour::onPageEvent function in Mozilla Firefox before 36.0 does not ensure that an API call originates from a foreground tab, which allows remote attackers to conduct spoofing and clickjacking attacks by leveraging access to a UI Tour web site.

IndexedDB should be cleared when leaving private browsing mode and it is not, the API for WKWebViewConfiguration was being used incorrectly and requires the private instance of this object be deleted when leaving private mode. This vulnerability affects Firefox for iOS < 27.

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.

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.

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.

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.