When styling and rendering an oversized `<select>` element, Firefox did not apply correct clipping which allowed an attacker to paint over the user interface. This vulnerability affects Firefox < 89.

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 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.

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.

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.

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.

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.

By misusing a race in our notification code, an attacker could have forcefully hidden the notification for pages that had received full screen and pointer lock access, which could have been used for spoofing attacks. This vulnerability affects Thunderbird < 91.4.0, Firefox ESR < 91.4.0, and Firefox < 95.

Thunderbird unexpectedly enabled JavaScript in the composition area. The JavaScript execution context was limited to this area and did not receive chrome-level privileges, but could be used as a stepping stone to further an attack with other vulnerabilities. This vulnerability affects Thunderbird < 91.4.0.

Through a series of navigations, Firefox could have entered fullscreen mode without notification or warning to the user. This could lead to spoofing attacks on the browser UI including phishing. This vulnerability affects Firefox < 94, Thunderbird < 91.3, and Firefox ESR < 91.3.

Through use of reportValidity() and window.open(), a plain-text validation message could have been overlaid on another origin, leading to possible user confusion and spoofing attacks. This vulnerability affects Firefox < 93, Thunderbird < 91.2, and Firefox ESR < 91.2.

Mixed-content checks were unable to analyze opaque origins which led to some mixed content being loaded. This vulnerability affects Firefox < 92.

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.

The Opportunistic Encryption feature of HTTP2 (RFC 8164) allows a connection to be transparently upgraded to TLS while retaining the visual properties of an HTTP connection, including being same-origin with unencrypted connections on port 80. However, if a second encrypted port on the same IP address (e.g. port 8443) did not opt-in to opportunistic encryption; a network attacker could forward a connection from the browser to port 443 to port 8443, causing the browser to treat the content of port 8443 as same-origin with HTTP. This was resolved by disabling the Opportunistic Encryption feature, which had low usage. This vulnerability affects Firefox < 94, Thunderbird < 91.3, and Firefox ESR < 91.3.

Due to an unusual sequence of attacker-controlled events, a Javascript alert() dialog with arbitrary (although unstyled) contents could be displayed over top an uncontrolled webpage of the attacker's choosing. This vulnerability affects Firefox < 94, Thunderbird < 91.3, and Firefox ESR < 91.3.

By displaying a form validity message in the correct location at the same time as a permission prompt (such as for geolocation), the validity message could have obscured the prompt, resulting in the user potentially being tricked into granting the permission. This vulnerability affects Firefox < 94, Thunderbird < 91.3, and Firefox ESR < 91.3.

When delegating navigations to the operating system, Firefox would accept the `mk` scheme which might allow attackers to launch pages and execute scripts in Internet Explorer in unprivileged mode. *This bug only affects Firefox for Windows. Other operating systems are unaffected.*. This vulnerability affects Firefox < 92, Thunderbird < 91.1, Thunderbird < 78.14, Firefox ESR < 78.14, and Firefox ESR < 91.1.

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.

When a user has already allowed a website to access microphone and camera, disabling camera sharing would not fully prevent the website from re-enabling it without an additional prompt. This was only possible if the website kept recording with the microphone until re-enabling the camera. This vulnerability affects Firefox < 89.

If a MIME encoded email contains an OpenPGP inline signed or encrypted message part, but also contains an additional unprotected part, Thunderbird did not indicate that only parts of the message are protected. This vulnerability affects Thunderbird < 78.10.2.

Through a series of DOM manipulations, a message, over which the attacker had control of the text but not HTML or formatting, could be overlaid on top of another domain (with the new domain correctly shown in the address bar) resulting in possible user confusion. This vulnerability affects Firefox < 90.

Address bar search suggestions in private browsing mode were re-using session data from normal mode. *This bug only affects Firefox for Android. Other operating systems are unaffected.*. This vulnerability affects Firefox < 89.

A malicious website that causes an HTTP Authentication dialog to be spawned could trick the built-in password manager to suggest passwords for the currently active website instead of the website that triggered the dialog. *This bug only affects Firefox for Android. Other operating systems are unaffected.*. This vulnerability affects Firefox < 89.

A possible vulnerability exists where type confusion can occur when manipulating JavaScript objects in object groups, allowing for the bypassing of security checks within these groups. *Note: this vulnerability has only been demonstrated with UnboxedObjects, which are disabled by default on all supported releases.*. This vulnerability affects Thunderbird < 60.7, Firefox < 67, and Firefox ESR < 60.7.

The DOMParser API did not properly process '<noscript>' elements for escaping. This could be used as an mXSS vector to bypass an HTML Sanitizer. This vulnerability affects Firefox < 86.

The developer page about:memory has a Measure function for exploring what object types the browser has allocated and their sizes. When this function was invoked we incorrectly called the sizeof function, instead of using the API method that checks for invalid pointers. This vulnerability affects Firefox < 86.

When sharing geolocation during an active WebRTC share, Firefox could have reset the webRTC sharing state in the user interface, leading to loss of control over the currently granted permission. This vulnerability affects Firefox < 85.

Through complicated navigations with new windows, an HTTP page could have inherited a secure lock icon from an HTTPS page. This vulnerability affects Firefox ESR < 78.10, Thunderbird < 78.10, and Firefox < 88.

A compromised content process could have performed session history manipulations it should not have been able to due to testing infrastructure that was not restricted to testing-only configurations. This vulnerability affects Firefox < 88.

An attacker may perform a DoS attack to prevent a user from sending encrypted email to a correspondent. If an attacker creates a crafted OpenPGP key with a subkey that has an invalid self signature, and the Thunderbird user imports the crafted key, then Thunderbird may try to use the invalid subkey, but the RNP library rejects it from being used, causing encryption to fail. This vulnerability affects Thunderbird < 78.9.1.

The browser could have been confused into transferring a pointer lock state into another tab, which could have lead to clickjacking attacks. This vulnerability affects Firefox < 85.

Mozilla Firefox before 20.0 on Android uses world-writable and world-readable permissions for the app_tmp installation directory in the local filesystem, which allows attackers to modify add-ons before installation via an application that leverages the time window during which app_tmp is used.

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.

If an XML file is served with a Content Security Policy and the XML file includes an XSL stylesheet, the Content Security Policy will not be applied to the contents of the XSL stylesheet. If the XSL sheet e.g. includes JavaScript, it would bypass any of the restrictions of the Content Security Policy applied to the XML document. This vulnerability affects Firefox < 72.

If upgrade-insecure-requests was specified in the Content Security Policy, and a link was dragged and dropped from that page, the link was not upgraded to https. This vulnerability affects Firefox < 70.

The "Forget about this site" feature in the History pane is intended to remove all saved user data that indicates a user has visited a site. This includes removing any HTTP Strict Transport Security (HSTS) settings received from sites that use it. Due to a bug, sites on the pre-load list also have their HSTS setting removed. On the next visit to that site if the user specifies an http: URL rather than secure https: they will not be protected by the pre-loaded HSTS setting. After that visit the site's HSTS setting will be restored. This vulnerability affects Firefox < 69 and Firefox ESR < 68.1.

The unicode latin 'kra' character can be used to spoof a standard 'k' character in the addressbar. This allows for domain spoofing attacks as do not display as punycode text, allowing for user confusion. This vulnerability affects Firefox < 68.

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."

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 2.0.0.8 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.

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

When a JavaScript URL (javascript:) is evaluated and the result is a string, this string is parsed to create an HTML document, which is then presented. Previously, this document's URL (as reported by the document.location property, for example) was the originating javascript: URL which could lead to spoofing attacks; it is now correctly the URL of the originating document. This vulnerability affects Firefox < 74.

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.

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.

Cross-site scripting (XSS) vulnerability in Mozilla Firefox before 2.0.0.5 allows remote attackers to inject arbitrary web script "into another site's context" via a "timing issue" involving the (1) addEventListener or (2) setTimeout function, probably by setting events that activate after the context has changed.

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.

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 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.