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.

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.

RSS fields can inject new lines into the created email structure, modifying the message body. This vulnerability affects Thunderbird < 52.5.2.

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.

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.

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.

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.

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.

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.

The System Only Wrapper (SOW) implementation in Mozilla Firefox before 27.0, Firefox ESR 24.x before 24.3, Thunderbird before 24.3, and SeaMonkey before 2.24 does not prevent certain cloning operations, which allows remote attackers to bypass intended restrictions on XUL content via vectors involving XBL content scopes.

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.

Mozilla Firefox before 29.0 on Android allows remote attackers to spoof the address bar via crafted JavaScript code that uses DOM events to prevent the reemergence of the actual address bar after scrolling has taken it off of the screen.

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.

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.

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.

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.

Bugzilla 2.16rc1 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 does not prevent changes to the confirmation e-mail address (aka old_email field) for e-mail change notifications, which makes it easier for remote attackers to perform arbitrary address changes by leveraging an unattended workstation.

Mozilla Firefox before 3.6.18, Thunderbird before 3.1.11, and SeaMonkey through 2.0.14 do not distinguish between cookies for two domain names that differ only in a trailing dot, which allows remote web servers to bypass the Same Origin Policy via Set-Cookie headers.

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.

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.

The fullscreen notification is prematurely hidden when fullscreen is re-requested quickly by the user. This could have been leveraged to perform a potential spoofing attack. This vulnerability affects Firefox < 135 and Thunderbird < 135.