The XMLHttpRequest object (XMLHTTP) in Netscape 6.1 and Mozilla 0.9.7 allows remote attackers to read arbitrary files and list directories on a client system by opening a URL that redirects the browser to the file on the client, then reading the result using the responseText property.

The Internationalized Domain Name (IDN) display algorithm in Mozilla Firefox before 22.0 does not properly handle the .com, .name, and .net top-level domains, which allows remote attackers to spoof the address bar via unspecified homograph characters.

Mozilla Firefox before 18.0, Firefox ESR 10.x before 10.0.12 and 17.x before 17.0.2, Thunderbird before 17.0.2, Thunderbird ESR 10.x before 10.0.12 and 17.x before 17.0.2, and SeaMonkey before 2.15 allow remote attackers to spoof the address bar via vectors involving authentication information in the userinfo field of a URL, in conjunction with a 204 (aka No Content) HTTP status code.

Mozilla Firefox before 5.0 does not properly enforce the whitelist for the xpinstall functionality, which allows remote attackers to trigger an installation dialog for a (1) add-on or (2) theme via unspecified vectors.

The CSSLoaderImpl::DoSheetComplete function in layout/style/nsCSSLoader.cpp in Mozilla Firefox 3.0.x before 3.0.18, 3.5.x before 3.5.8, and 3.6.x before 3.6.2; Thunderbird before 3.0.2; and SeaMonkey before 2.0.3 changes the case of certain strings in a stylesheet before adding this stylesheet to the XUL cache, which might allow remote attackers to modify the browser's font and other CSS attributes, and potentially disrupt rendering of a web page, by forcing the browser to perform this erroneous stylesheet caching.

A crafted S/MIME message consisting of an inner encryption layer and an outer SignedData layer was shown as having a valid digital signature, although the signer might have had no access to the contents of the encrypted message, and might have stripped a different signature from the encrypted message. Previous versions had only suppressed showing a digital signature for messages with an outer multipart/signed layer. This vulnerability affects Thunderbird < 68.1.1.

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.

Firefox will accept any registered Program ID as an external protocol handler and offer to launch this local application when given a matching URL on Windows operating systems. This should only happen if the program has specifically registered itself as a "URL Handler" in the Windows registry. *Note: This issue only affects Windows operating systems. Other operating systems are unaffected.*. This vulnerability affects Thunderbird < 60.6, Firefox ESR < 60.6, and Firefox < 66.

When a new Firefox profile is created on 64-bit Windows installations, the sandbox for 64-bit NPAPI plugins is not enabled by default. Note: This issue only affects 64-bit Windows. 32-bit Windows and other operating systems are unaffected. This vulnerability affects Firefox < 50.

Auth/Verify/LDAP.pm in Bugzilla 2.x and 3.x before 3.6.11, 3.7.x and 4.0.x before 4.0.8, 4.1.x and 4.2.x before 4.2.3, and 4.3.x before 4.3.3 does not restrict the characters in a username, which might allow remote attackers to inject data into an LDAP directory via a crafted login attempt.

The location bar in Firefox for Android can be spoofed by forcing a user into fullscreen mode, blocking its exiting, and creating of a fake location bar without any user notification. Note: This issue only affects Firefox for Android. Other versions and operating systems are unaffected. This vulnerability affects Firefox < 50.

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.

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.

Mozilla Firefox before 27.0, Firefox ESR 24.x before 24.3, Thunderbird before 24.3, and SeaMonkey before 2.24 allow remote attackers to bypass intended restrictions on window objects by leveraging inconsistency in native getter methods across different JavaScript engines.

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.

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.

An audio capture session can started under an incorrect origin from the site making the capture request. Users are still prompted to allow the request but the prompt can display the wrong origin, leading to user confusion about which site is making the request to capture an audio stream. This vulnerability affects Firefox < 58.

Some Arabic and Indic vowel marker characters can be combined with Latin characters in a domain name to eclipse the non-Latin character with some font sets on the addressbar. The non-Latin character will not be visible to most viewers. This allows for domain spoofing attacks because these combined domain names do not display as punycode. This vulnerability affects Firefox < 57.

The confirm_create_account function in the account-creation feature in token.cgi in Bugzilla 2.x through 4.0.x before 4.0.15, 4.1.x and 4.2.x before 4.2.11, 4.3.x and 4.4.x before 4.4.6, and 4.5.x before 4.5.6 does not specify a scalar context for the realname parameter, which allows remote attackers to create accounts with unverified e-mail addresses by sending three realname values with realname=login_name as the second, as demonstrated by selecting an e-mail address with a domain name for which group privileges are automatically granted.

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.

If Media Capture and Streams API permission is requested from documents with "data:" or "blob:" URLs, the permission notifications do not properly display the originating domain. The notification states "Unknown protocol" as the requestee, leading to user confusion about which site is asking for this permission. This vulnerability affects Firefox < 59.

Sites can bypass security checks on permissions to install lightweight themes by manipulating the "baseURI" property of the theme element. This could allow a malicious site to install a theme without user interaction which could contain offensive or embarrassing images. This vulnerability affects Thunderbird < 52.8, Thunderbird ESR < 52.8, Firefox < 60, and Firefox ESR < 52.8.

If cursor visibility is toggled by script using from 'none' to an image and back through script, the cursor will be rendered temporarily invisible within Firefox. Note: This vulnerability only affects OS X. Other operating systems are not affected. This vulnerability affects Firefox < 58.

A spoofing vulnerability can occur when a malicious site with an extremely long domain name is opened in an Android Custom Tab (a browser panel inside another app) and the default browser is Firefox for Android. This could allow an attacker to spoof which page is actually loaded and in use. Note: this issue only affects Firefox for Android. Other versions and operating systems are unaffected. This vulnerability affects Firefox < 59.

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.

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.

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.

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.

Improved Host header checks to reject requests not sent to a well-known local hostname or IP, or the server-specified hostname.

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."

Documents formed using data: URLs in an OBJECT element failed to inherit the CSP of the creating context. This allowed the execution of scripts that should have been blocked, albeit with a unique opaque origin. This vulnerability affects Firefox < 76.

Mozilla Firefox 4.x through 9.0, Thunderbird 5.0 through 9.0, and SeaMonkey before 2.7 allow remote attackers to bypass the HTML5 frame-navigation policy and replace arbitrary sub-frames by creating a form submission target with a sub-frame's name attribute.

If WebRTC permission is requested from documents with data: or blob: URLs, the permission notifications do not properly display the originating domain. The notification states "Unknown origin" as the requestee, leading to user confusion about which site is asking for this permission. This vulnerability affects Firefox < 66.

A flaw during verification of certain S/MIME signatures causes emails to be shown in Thunderbird as having a valid digital signature, even if the shown message contents aren't covered by the signature. The flaw allows an attacker to reuse a valid S/MIME signature to craft an email message with arbitrary content. This vulnerability affects Thunderbird < 60.5.1.

Mozilla Firefox before 43.0 mishandles the # (number sign) character in a data: URI, which allows remote attackers to spoof web sites via unspecified vectors.

Mozilla Firefox 4.x through 13.0, Firefox ESR 10.x before 10.0.6, Thunderbird 5.0 through 13.0, Thunderbird ESR 10.x before 10.0.6, and SeaMonkey before 2.11 do not consider the presence of same-compartment security wrappers (SCSW) during the cross-compartment wrapping of objects, which allows remote attackers to bypass intended XBL access restrictions via crafted content.

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 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.

Manually dragging and dropping an Outlook email message into the browser will trigger a page navigation when the message's mail columns are incorrectly interpreted as a URL. *Note: this issue only affects Windows operating systems with Outlook installed. Other operating systems are not affected.*. This vulnerability affects Firefox ESR < 60.2 and Firefox < 62.

If a site is loaded over a HTTPS connection but loads a favicon resource over HTTP, the mixed content warning is not displayed to users. This vulnerability affects Firefox < 63.

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.*

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.

email_in.pl in Bugzilla 2.23.4 through 3.0.0 allows remote attackers to execute arbitrary commands via the -f (From address) option to the Email::Send::Sendmail function, probably involving shell metacharacters.

SVG loaded through "<img>" tags can use "<meta>" tags within the SVG data to set cookies for that page. This vulnerability affects Firefox < 57.

When a page's content security policy (CSP) header contains a "sandbox" directive, other directives are ignored. This results in the incorrect enforcement of CSP. This vulnerability affects Thunderbird < 52.3, Firefox ESR < 52.3, and Firefox < 55.

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.

The "instanceof" operator can bypass the Xray wrapper mechanism. When called on web content from the browser itself or an extension the web content can provide its own result for that operator, possibly tricking the browser or extension into mishandling the element. This vulnerability affects Firefox < 56.

An error in the "WindowsDllDetourPatcher" where a RWX ("Read/Write/Execute") 4k block is allocated but never protected, violating DEP protections. Note: This attack only affects Windows operating systems. Other operating systems are not affected. This vulnerability affects Thunderbird < 52.3, Firefox ESR < 52.3, and Firefox < 55.

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.

When entered directly, Reader Mode did not strip the username and password section of URLs displayed in the addressbar. This can be used for spoofing the domain of the current page. This vulnerability affects Firefox < 54.