On pages containing an iframe, the "data:" protocol can be used to create a modal alert that will render over arbitrary domains following page navigation, spoofing of the origin of the modal alert from the iframe content. This vulnerability affects Thunderbird < 52.3, Firefox ESR < 52.3, and Firefox < 55.

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.

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.

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.

If a server sends two Strict-Transport-Security (STS) headers for a single connection, they will be rejected as invalid and HTTP Strict Transport Security (HSTS) will not be enabled for the connection. This vulnerability affects Firefox < 55.

It is possible to spoof the sender's email address and display an arbitrary sender address to the email recipient. The real sender's address is not displayed if preceded by a null character in the display string. This vulnerability affects Thunderbird < 52.5.2.

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.

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.

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.

The internal feed reader APIs that crossed the sandbox barrier allowed for a sandbox escape and escalation of privilege if combined with another vulnerability that resulted in remote code execution inside the sandboxed process. This vulnerability affects Firefox ESR < 52.1 and Firefox < 53.

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.

When dragging content from the primary browser pane to the addressbar on a malicious site, it is possible to change the addressbar so that the displayed location following navigation does not match the URL of the newly loaded page. This allows for spoofing attacks. This vulnerability affects Firefox < 52.

A malicious site could spoof the contents of the print preview window if popup windows are enabled, resulting in user confusion of what site is currently loaded. This vulnerability affects Firefox < 52 and Thunderbird < 52.

The CSS parser in 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 ignores the '\0' escaped null character, which might allow remote attackers to bypass protection mechanisms such as sanitization routines.

Mozilla Firefox before 2.0.0.13 and SeaMonkey before 1.1.9, when generating the HTTP Referer header, does not list the entire URL when it contains Basic Authentication credentials without a username, which makes it easier for remote attackers to bypass application protection mechanisms that rely on Referer headers, such as with some Cross-Site Request Forgery (CSRF) mechanisms.

Mozilla Firefox before 2.0.0.12 does not always display a web forgery warning dialog if the entire contents of a web page are in a DIV tag that uses absolute positioning, which makes it easier for remote attackers to conduct phishing attacks.

Mozilla Firefox 2.0.0.11, 3.0b2, and possibly earlier versions, when prompting for HTTP Basic Authentication, displays the site requesting the authentication after the Realm text, which might make it easier for remote HTTP servers to conduct phishing and spoofing attacks.

Mozilla Firefox 2.0.0.1 through 2.0.0.3 does not canonicalize URLs before checking them against the phishing site blacklist, which allows remote attackers to bypass phishing protection via multiple / (slash) characters in the URL.

The crypto.signText function in Mozilla Firefox and Thunderbird before 1.5.0.4 allows remote attackers to execute arbitrary code via certain optional Certificate Authority name arguments, which causes an invalid array index and triggers a buffer overflow.

Mozilla Firefox before 1.0 truncates long filenames in the file download dialog box, which makes it easier for remote attackers to trick users into downloading files with dangerous extensions.

The JavaScript engine in Mozilla Firefox and Thunderbird 1.x before 1.5 and 1.0.x before 1.0.8, Mozilla Suite before 1.7.13, and SeaMonkey before 1.0 does not properly handle temporary variables that are not garbage collected, which might allow remote attackers to trigger operations on freed memory and cause memory corruption.

Firefox 1.5.0.1 allows remote attackers to spoof the address bar and possibly conduct phishing attacks by re-opening the window to a malicious Shockwave Flash application, then changing the window location back to a trusted URL while the Flash application is still loading. NOTE: a followup was unable to replicate this issue.

Firefox before 1.0 and Mozilla before 1.7.5 allows inactive (background) tabs to launch dialog boxes, which can allow remote attackers to spoof the dialog boxes from web sites in other windows and facilitate phishing attacks, aka the "Dialog Box Spoofing Vulnerability."

process_bug.cgi in Bugzilla 2.9 through 2.18rc2 and 2.19 from CVS does not check edit permissions on the keywords field, which allows remote authenticated users to modify the keywords in a bug via the keywordaction parameter.

Mozilla Firefox 1.0.1 and possibly other versions, including Mozilla and Thunderbird, allows remote attackers to spoof the URL in the Status Bar via an A HREF tag that contains a TABLE tag that contains another A tag.

Mozilla Firefox before 2.0.0.15 and SeaMonkey before 1.1.10 allow remote attackers to force the upload of arbitrary local files from a client computer via vectors involving originalTarget and DOM Range.

The XULDocument.persist function in Mozilla, Firefox before 1.5.0.1, and SeaMonkey before 1.0 does not validate the attribute name, which allows remote attackers to execute arbitrary Javascript by injecting RDF data into the user's localstore.rdf file.

Mozilla before 1.7, Firefox before 0.9, and Thunderbird before 0.7, allow remote web sites to install arbitrary extensions by using interactive events to manipulate the XPInstall Security dialog box.

Mozilla Firefox 0.9.1 and 0.9.2 allows remote web sites to spoof certificates of trusted web sites via redirects and Javascript that uses the "onunload" method.

Mozilla before 1.7, Firefox before 0.9, and Thunderbird before 0.7, allow remote attackers to use certain redirect sequences to spoof the security lock icon that makes a web page appear to be encrypted.

The InstallTrigger.install method in Firefox before 1.0.5 and Mozilla before 1.7.9 allows remote attackers to execute a callback function in the context of another domain by forcing a page navigation after the install method has been called, which causes the callback to be run in the context of the new page and results in a same origin violation.

Firefox before 1.0.7 and Mozilla Suite before 1.7.12 allows remote attackers to spawn windows without user interface components such as the address and status bar, which could be used to conduct spoofing or phishing attacks.

Firefox, when opening Microsoft Word documents, does not properly set the permissions on shared sections, which allows remote attackers to write arbitrary data to open applications in Microsoft Office.

Firefox before 1.0.7 and Mozilla Suite before 1.7.12 allows remote attackers to modify HTTP headers of XML HTTP requests via XMLHttpRequest, and possibly use the client to exploit vulnerabilities in servers or proxies, including HTTP request smuggling and HTTP request splitting.

The Flag::validate and Flag::modify functions in Bugzilla 2.17.1 to 2.18.1 and 2.19.1 to 2.19.3 do not verify that the flag ID is appropriate for the given bug or attachment ID, which allows users to change flags on arbitrary bugs and obtain a bug summary via process_bug.cgi.

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.

Mozilla Firefox 2.0.0.6 and earlier allows remote attackers to spoof the contents of the status bar via a link to a data: URI containing an encoded URL. NOTE: the severity of this issue has been disputed by a reliable third party, since the intended functionality of the status bar allows it to be modified.

The file download dialog in Mozilla Firefox 0.10.1 and 1.0 for Windows allows remote attackers to hide the real file types of downloaded files via the Content-Type HTTP header and a filename containing whitespace, dots, or ASCII byte 160.

Thunderbird 0.6 through 0.9 and Mozilla 1.7 through 1.7.3 does not obey the network.cookie.disableCookieForMailNews preference, which could allow remote attackers to bypass the user's intended privacy and security policy by using cookies in e-mail messages.

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.

Firefox before 1.0 allows the user to store a (1) javascript: or (2) data: URLs as a Livefeed bookmark, then executes it in the security context of the currently loaded page when the user later accesses the bookmark, which could allow remote attackers to execute arbitrary code.

Mozilla Firefox before 0.10.1 allows remote attackers to delete arbitrary files in the download directory via a crafted data: URI that is not properly handled when the user clicks the Save button.

A lack of parameter validation on IPC messages results in a potential out-of-bounds write through malformed IPC messages. This can potentially allow for sandbox escape through memory corruption in the parent process. This vulnerability affects Thunderbird < 52.7, Firefox ESR < 52.7, and Firefox < 59.

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.

In the Windows 10 April 2018 Update, Windows Defender SmartScreen honors the "SEE_MASK_FLAG_NO_UI" flag associated with downloaded files and will not show any UI. Files that are unknown and potentially dangerous will be allowed to run because SmartScreen will not prompt the user for a decision, and if the user is offline all files will be allowed to be opened because Windows won't prompt the user to ask what to do. Firefox incorrectly sets this flag when downloading files, leading to less secure behavior from SmartScreen. Note: this issue only affects Windows 10 users running the April 2018 update or later. It does not affect other Windows users or other operating systems. This vulnerability affects Thunderbird < 52.8, Thunderbird ESR < 52.8, Firefox < 60, and Firefox ESR < 52.8.

WebExtensions can bypass normal restrictions in some circumstances and use "browser.tabs.executeScript" to inject scripts into contexts where this should not be allowed, such as pages from other WebExtensions or unprivileged "about:" pages. This vulnerability affects Firefox < 59.

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 right-to-left text is used in the addressbar with left-to-right alignment, it is possible in some circumstances to scroll this text to spoof the displayed URL. This issue could result in the wrong URL being displayed as a location, which can mislead users to believe they are on a different site than the one loaded. This vulnerability affects Thunderbird < 52.6, Firefox ESR < 52.6, and Firefox < 58.

In 32-bit versions of Firefox, the Adobe Flash plugin setting for "Enable Adobe Flash protected mode" is unchecked by default even though the Adobe Flash sandbox is actually enabled. The displayed state is the reverse of the true setting, resulting in user confusion. This could cause users to select this setting intending to activate it and inadvertently turn protections off. This vulnerability affects Firefox < 60.

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.*