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.

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.

Cross-site scripting (XSS) vulnerability in Mozilla Firefox 4.x through 11.0, Firefox ESR 10.x before 10.0.4, Thunderbird 5.0 through 11.0, Thunderbird ESR 10.x before 10.0.4, and SeaMonkey before 2.9 allows remote attackers to inject arbitrary web script or HTML via a multibyte character set.

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.

Multiple cross-site scripting (XSS) vulnerabilities in Mozilla Firefox 4.x through 11.0, Firefox ESR 10.x before 10.0.4, Thunderbird 5.0 through 11.0, Thunderbird ESR 10.x before 10.0.4, and SeaMonkey before 2.9 allow remote attackers to inject arbitrary web script or HTML via the (1) ISO-2022-KR or (2) ISO-2022-CN character set.

Cross-site scripting (XSS) vulnerability in the docshell implementation in Mozilla Firefox 4.x through 11.0, Firefox ESR 10.x before 10.0.4, Thunderbird 5.0 through 11.0, Thunderbird ESR 10.x before 10.0.4, and SeaMonkey before 2.9 allows remote attackers to inject arbitrary web script or HTML via vectors related to short-circuited page loads, aka "Universal XSS (UXSS)."

A "data:" URL loaded in a new tab did not inherit the Content Security Policy (CSP) of the original page, allowing for bypasses of the policy including the execution of JavaScript. In prior versions when "data:" documents also inherited the context of the original page this would allow for potential cross-site scripting (XSS) attacks. This vulnerability affects Firefox < 57.

CRLF injection vulnerability in Mozilla Firefox 4.x through 10.0, Firefox ESR 10.x before 10.0.3, Thunderbird 5.0 through 10.0, Thunderbird ESR 10.x before 10.0.3, and SeaMonkey before 2.8 allows remote web servers to bypass intended Content Security Policy (CSP) restrictions and possibly conduct cross-site scripting (XSS) attacks via crafted HTTP headers.

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.

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.

Control characters prepended before "javascript:" URLs pasted in the addressbar can cause the leading characters to be ignored and the pasted JavaScript to be executed instead of being blocked. This could be used in social engineering and self-cross-site-scripting (self-XSS) attacks where users are convinced to copy and paste text into the addressbar. This vulnerability affects Firefox < 57.

Mozilla Firefox before 3.6.28 and 4.x through 10.0, Firefox ESR 10.x before 10.0.3, Thunderbird before 3.1.20 and 5.0 through 10.0, Thunderbird ESR 10.x before 10.0.3, and SeaMonkey before 2.8 do not properly restrict drag-and-drop operations on javascript: URLs, which allows user-assisted remote attackers to conduct cross-site scripting (XSS) attacks via a crafted web page, related to a "DragAndDropJacking" issue.

Mozilla Firefox 4.x through 11.0, Firefox ESR 10.x before 10.0.4, Thunderbird 5.0 through 11.0, Thunderbird ESR 10.x before 10.0.4, and SeaMonkey before 2.9 allow remote attackers to spoof the address bar via an https URL for invalid (1) RSS or (2) Atom XML content.

If a page is loaded from an original site through a hyperlink and contains a redirect to a "data:text/html" URL, triggering a reload will run the reloaded "data:text/html" page with its origin set incorrectly. This allows for a cross-site scripting (XSS) attack. 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.

A "javascript:" url loaded by a malicious page can obfuscate its location by blanking the URL displayed in the addressbar, allowing for an attacker to spoof an existing page without the malicious page's address being displayed correctly. This vulnerability affects Firefox < 52.

The "mozAddonManager" allows for the installation of extensions from the CDN for addons.mozilla.org, a publicly accessible site. This could allow malicious extensions to install additional extensions from the CDN in combination with an XSS attack on Mozilla AMO sites. This vulnerability affects Firefox < 51.

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.

Lack of escaping allowed HTML injection when a webpage was viewed in Reader View. While a Content Security Policy prevents direct code execution, HTML injection is still possible. *Note: This issue only affected Firefox for Android. Other operating systems are unaffected.*. This vulnerability affects Firefox < 88.

A malicious webpage could have forced a Firefox for Android user into executing attacker-controlled JavaScript in the context of another domain, resulting in a Universal Cross-Site Scripting vulnerability. *Note: This issue only affected Firefox for Android. Other operating systems are unaffected. Further details are being temporarily withheld to allow users an opportunity to update.*. This vulnerability affects Firefox < 88.0.1 and Firefox for Android < 88.1.3.

Cross-site scripting (XSS) vulnerability in Mozilla Firefox before 3.6.24 and 4.x through 7 allows remote attackers to inject arbitrary web script or HTML via vectors involving HTTP 0.9 errors, non-default ports, and content-sniffing.

Cross-site scripting (XSS) vulnerability in Mozilla Firefox before 3.6.24 and 4.x through 7.0 and Thunderbird before 3.1.6 and 5.0 through 7.0 allows remote attackers to inject arbitrary web script or HTML via crafted text with Shift JIS encoding.

Multiple cross-site scripting (XSS) vulnerabilities in Bugzilla 2.x and 3.x before 3.4.13, 3.5.x and 3.6.x before 3.6.7, 3.7.x and 4.0.x before 4.0.3, and 4.1.x through 4.1.3, when debug mode is used, allow remote attackers to inject arbitrary web script or HTML via vectors involving a (1) tabular report, (2) graphical report, or (3) new chart.

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.

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.

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.

Mozilla Firefox before 3.6.23 and 4.x through 5, Thunderbird before 6.0, and SeaMonkey before 2.3 do not properly handle "location" as the name of a frame, which allows remote attackers to bypass the Same Origin Policy via a crafted web site, a different vulnerability than CVE-2010-0170.

Firefox for Android could get stuck in fullscreen mode and not exit it even after normal interactions that should cause it to exit. *Note: This issue only affected Firefox for Android. Other operating systems are unaffected.*. This vulnerability affects Firefox < 91.

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.

CRLF injection vulnerability in Bugzilla 2.17.1 through 2.22.7, 3.0.x through 3.3.x, 3.4.x before 3.4.12, 3.5.x, 3.6.x before 3.6.6, 3.7.x, 4.0.x before 4.0.2, and 4.1.x before 4.1.3 allows remote attackers to inject arbitrary e-mail headers via an attachment description in a flagmail notification.

Mozilla Firefox before 3.6 is vulnerable to XSS via the rendering of Cascading Style Sheets

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.

Cross-site scripting (XSS) vulnerability in Bugzilla 2.16rc1 through 2.22.7, 3.0.x through 3.3.x, and 3.4.x before 3.4.12 allows remote attackers to inject arbitrary web script or HTML via vectors involving a BUGLIST cookie.

Cross-site scripting (XSS) vulnerability in Mozilla Firefox 4.x through 4.0.1 allows remote attackers to inject arbitrary web script or HTML via an SVG element containing an HTML-encoded entity.

The JSSubScriptLoader in Mozilla Firefox 4.x through 6 and SeaMonkey before 2.4 does not properly handle XPCNativeWrappers during calls to the loadSubScript method in an add-on, which makes it easier for remote attackers to gain privileges via a crafted web site that leverages certain unwrapping behavior.

Mozilla Firefox before 3.6.23 and 4.x through 6, Thunderbird before 7.0, and SeaMonkey before 2.4 do not properly handle HTTP responses that contain multiple Location, Content-Length, or Content-Disposition headers, which makes it easier for remote attackers to conduct HTTP response splitting attacks via crafted header values.

Mozilla Firefox 4.x through 6, Thunderbird before 7.0, and SeaMonkey before 2.4 do not prevent manual add-on installation in response to the holding of the Enter key, which allows user-assisted remote attackers to bypass intended access restrictions via a crafted web site that triggers an unspecified internal error.

Cross-site scripting (XSS) vulnerability in Bugzilla 2.4 through 2.22.7, 3.0.x through 3.3.x, 3.4.x before 3.4.12, 3.5.x, 3.6.x before 3.6.6, 3.7.x, 4.0.x before 4.0.2, and 4.1.x before 4.1.3, when Internet Explorer before 9 or Safari before 5.0.6 is used for Raw Unified mode, allows remote attackers to inject arbitrary web script or HTML via a crafted patch, related to content sniffing.

CRLF injection vulnerability in the nsCookieService::SetCookieStringInternal function in netwerk/cookie/nsCookieService.cpp in Mozilla Firefox before 3.6.18 and 4.x through 4.0.1, and Thunderbird before 3.1.11, allows remote attackers to bypass intended access restrictions via a string containing a \n (newline) character, which is not properly handled in a JavaScript "document.cookie =" expression, a different vulnerability than CVE-2011-2374.

Event handlers on "marquee" elements were executed despite a strict Content Security Policy (CSP) that disallowed inline JavaScript. This vulnerability affects Firefox < 50.1, Firefox ESR < 45.6, and Thunderbird < 45.6.

Cross-site scripting (XSS) vulnerability in the quips feature in Mozilla Bugzilla 2.10 through 2.17 allows remote attackers to inject arbitrary web script or HTML via the "show all quips" page.

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.

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.

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 creates a clickable link for a (1) javascript: or (2) data: URI in the URL (aka bug_file_loc) field, which allows remote attackers to conduct cross-site scripting (XSS) attacks against logged-out users via a crafted URI.

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.

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.

By utilizing 3D CSS in conjunction with Javascript, content could have been rendered outside the webpage's viewport, resulting in a spoofing attack that could have been used for phishing or other attacks on a user. This vulnerability affects Firefox < 88.

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.

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.