When protecting CSS blocks with the nonce feature of Content Security Policy, the @import statement in the CSS block could allow an attacker to inject arbitrary styles, bypassing the intent of the Content Security Policy. This vulnerability affects Firefox < 74.

Visual truncation vulnerability in Mozilla Firefox before 3.0.14, and 3.5.x before 3.5.3, allows remote attackers to trigger a vertical scroll and spoof URLs via unspecified Unicode characters with a tall line-height property.

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 International Domain Name (IDN) support in Epiphany allows remote attackers to spoof domain names using punycode encoded domain names that are decoded in URLs and SSL certificates in a way that uses homograph characters from other character sets, which facilitates phishing attacks.

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 Firefox before 40.0 and Firefox ESR 38.x before 38.2 do not impose certain ECMAScript 6 requirements on JavaScript object properties, which allows remote attackers to bypass the Same Origin Policy via the reviver parameter to the JSON.parse method.

Mozilla Firefox before 36.0 does not properly recognize the equivalence of domain names with and without a trailing . (dot) character, which allows man-in-the-middle attackers to bypass the HPKP and HSTS protection mechanisms by constructing a URL with this character and leveraging access to an X.509 certificate for a domain with this character.

Mozilla Firefox before 37.0, Firefox ESR 31.x before 31.6, and Thunderbird before 31.6 do not properly restrict resource: URLs, which makes it easier for remote attackers to execute arbitrary JavaScript code with chrome privileges by leveraging the ability to bypass the Same Origin Policy, as demonstrated by the resource: URL associated with PDF.js.

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

Mozilla Firefox before 30.0 and Thunderbird through 24.6 on OS X do not ensure visibility of the cursor after interaction with a Flash object and a DIV element, which makes it easier for remote attackers to conduct clickjacking attacks via JavaScript code that produces a fake cursor image.

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.

The Pocket toolbar button, once activated, listens for events fired from it's own pages but does not verify the origin of incoming events. This allows content from other origins to fire events and inject content and commands into the Pocket context. Note: this issue does not affect users with e10s enabled. This vulnerability affects Firefox ESR < 45.6 and Firefox < 50.1.

WebExtensions can bypass security checks to load privileged URLs and potentially escape the WebExtension sandbox. This vulnerability affects Firefox < 50.

The "Mark of the Web" was not correctly saved on Windows when files with very long names were downloaded from the Internet. Without the Mark of the Web data, the security warning that Windows displays before running executables downloaded from the Internet is not shown. Note: This attack only affects Windows operating systems. Other operating systems are unaffected. This vulnerability affects Firefox < 54, Firefox ESR < 52.2, and Thunderbird < 52.2.

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.