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.

Mozilla Firefox before 1.5.0.7 and SeaMonkey before 1.0.5 allows remote attackers to bypass the security model and inject content into the sub-frame of another site via targetWindow.frames[n].document.open(), which facilitates spoofing and other attacks.

By encoding Unicode whitespace characters within the From email header, an attacker can spoof the sender email address that Thunderbird displays. This vulnerability affects Thunderbird < 68.8.0.

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.

Mozilla Firefox and Thunderbird before 1.5.0.4 strip the Unicode Byte-order-Mark (BOM) from a UTF-8 page before the page is passed to the parser, which allows remote attackers to conduct cross-site scripting (XSS) attacks via a BOM sequence in the middle of a dangerous tag such as SCRIPT.

Cross-site scripting (XSS) vulnerability in Mozilla Firefox before 1.5.0.4 allows user-assisted remote attackers to inject arbitrary web script or HTML by tricking a user into (1) performing a "View Image" on a broken image in which the SRC attribute contains a Javascript URL, or (2) selecting "Show only this frame" on a frame whose SRC attribute contains a Javascript URL.

Mozilla Firefox 1.x before 1.5 and 1.0.x before 1.0.8, Mozilla Suite before 1.7.13, and SeaMonkey before 1.0 allows remote attackers to inject arbitrary Javascript into other sites by (1) "using a modal alert to suspend an event handler while a new page is being loaded", (2) using eval(), and using certain variants involving (3) "new Script;" and (4) using window.__proto__ to extend eval, aka "cross-site JavaScript injection".

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 returns the Object class prototype instead of the global window object when (1) .valueOf.call or (2) .valueOf.apply are called without any arguments, which allows remote attackers to conduct cross-site scripting (XSS) attacks.

Unspecified vulnerability 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 allows remote attackers to bypass same-origin protections and conduct cross-site scripting (XSS) attacks via unspecified vectors involving the window.controllers array.

Cross-site scripting (XSS) vulnerability in Mozilla 1.7.12 and possibly earlier, Mozilla Firefox 1.0.7 and possibly earlier, and Netscape 8.1 and possibly earlier, allows remote attackers to inject arbitrary web script or HTML via the -moz-binding (Cascading Style Sheets) CSS property, which does not require that the style sheet have the same origin as the web page, as demonstrated by the compromise of a large number of LiveJournal accounts.

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 ensure that a scalar context is used for certain CGI parameters, which allows remote attackers to conduct cross-site scripting (XSS) attacks by sending three values for a single parameter name.

Cross-site scripting (XSS) vulnerability in Mozilla Thunderbird 17.x through 17.0.8, Thunderbird ESR 17.x through 17.0.10, and SeaMonkey before 2.20 allows user-assisted remote attackers to inject arbitrary web script or HTML via an e-mail message containing a data: URL in a (1) OBJECT or (2) EMBED element, a related issue to CVE-2013-6674.

A mechanism was discovered that removes some bounds checking for string, array, or typed array accesses if Spectre mitigations have been disabled. This vulnerability could allow an attacker to create an arbitrary value in compiled JavaScript, for which the range analysis will infer a fully controlled, incorrect range in circumstances where users have explicitly disabled Spectre mitigations. *Note: Spectre mitigations are currently enabled for all users by default settings.*. This vulnerability affects Thunderbird < 60.6, Firefox ESR < 60.6, and Firefox < 66.

Cross-site scripting (XSS) vulnerability in Bugzilla before 2.18, including 2.16.x before 2.16.11, allows remote attackers to inject arbitrary HTML and web script via forced error messages, as demonstrated using the action parameter.

Mozilla Firefox before 44.0 on Android allows remote attackers to spoof the address bar via the scrollTo method.

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.

Mozilla Firefox before 45.0 and Firefox ESR 38.x before 38.7 mishandle a navigation sequence that returns to the original page, which allows remote attackers to spoof the address bar via vectors involving the history.back method and the location.protocol property.

Mixed-content checks were unable to analyze opaque origins which led to some mixed content being loaded. This vulnerability affects Firefox < 92.

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.

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.

The file-download implementation in Mozilla Firefox before 27.0 and SeaMonkey before 2.24 does not properly restrict the timing of button selections, which allows remote attackers to conduct clickjacking attacks, and trigger unintended launching of a downloaded file, via a crafted web site.

Add-on updates failed to verify that the add-on ID inside the signed package matched the ID of the add-on being updated. An attacker who could perform a man-in-the-middle attack on the user's connection to the update server and defeat the certificate pinning protection could provide a malicious signed add-on instead of a valid update. This vulnerability affects Firefox ESR < 45.5 and Firefox < 50.

Cross-site scripting (XSS) vulnerability in a phone component in Cybozu Garoon before 3.7.0, when Internet Explorer or Firefox is used, allows remote attackers to inject arbitrary web script or HTML via unspecified vectors.

Cross-site scripting (XSS) vulnerability in a schedule component in Cybozu Garoon before 3.7.0, when Internet Explorer or Firefox is used, allows remote attackers to inject arbitrary web script or HTML via unspecified vectors.

Cross-site scripting (XSS) vulnerability in Mozilla Firefox before 26.0 and SeaMonkey before 2.23 makes it easier for remote attackers to inject arbitrary web script or HTML by leveraging a Same Origin Policy violation triggered by lack of a charset parameter in a Content-Type HTTP header.

Multiple cross-site scripting (XSS) vulnerabilities in report.cgi in Bugzilla 4.1.x and 4.2.x before 4.2.7 and 4.3.x and 4.4.x before 4.4.1 allow remote attackers to inject arbitrary web script or HTML via a field value that is not properly handled during construction of a tabular report, as demonstrated by the (1) summary or (2) real name field. NOTE: this issue exists because of an incomplete fix for CVE-2012-4189.

Multiple cross-site scripting (XSS) vulnerabilities in editflagtypes.cgi in Bugzilla 2.x, 3.x, and 4.0.x before 4.0.11; 4.1.x and 4.2.x before 4.2.7; and 4.3.x and 4.4.x before 4.4.1 allow remote attackers to inject arbitrary web script or HTML via the (1) id or (2) sortkey parameter.

JetBrains YouTrack versions before 2019.2.53938 had a possible XSS through issue attachments when using the Firefox browser.

Thunderbird did not check if the user ID associated with an OpenPGP key has a valid self signature. An attacker may create a crafted version of an OpenPGP key, by either replacing the original user ID, or by adding another user ID. If Thunderbird imports and accepts the crafted key, the Thunderbird user may falsely conclude that the false user ID belongs to the correspondent. This vulnerability affects Thunderbird < 78.9.1.

Mozilla Firefox before 17.0, Firefox ESR 10.x before 10.0.11, Thunderbird before 17.0, Thunderbird ESR 10.x before 10.0.11, and SeaMonkey before 2.14 implement cross-origin wrappers with a filtering behavior that does not properly restrict write actions, which allows remote attackers to conduct cross-site scripting (XSS) attacks via a crafted web site.

Mozilla Firefox before 16.0.2, Firefox ESR 10.x before 10.0.10, Thunderbird before 16.0.2, Thunderbird ESR 10.x before 10.0.10, and SeaMonkey before 2.13.2 do not prevent use of the valueOf method to shadow the location object (aka window.location), which makes it easier for remote attackers to conduct cross-site scripting (XSS) attacks via vectors involving a plugin.

When pasting a &lt;style&gt; tag from the clipboard into a rich text editor, the CSS sanitizer does not escape &lt; and &gt; characters. Because the resulting string is pasted directly into the text node of the element this does not result in a direct injection into the webpage; however, if a webpage subsequently copies the node's innerHTML, assigning it to another innerHTML, this would result in an XSS vulnerability. Two WYSIWYG editors were identified with this behavior, more may exist. This vulnerability affects Firefox ESR < 68.4 and Firefox < 72.

If upgrade-insecure-requests was specified in the Content Security Policy, and a link was dragged and dropped from that page, the link was not upgraded to https. This vulnerability affects Firefox < 70.

Mozilla Firefox before 16.0, Thunderbird before 16.0, and SeaMonkey before 2.13 do not properly implement the HTML5 Same Origin Policy, which allows remote attackers to conduct cross-site scripting (XSS) attacks by leveraging initial-origin access after document.domain has been set.

When pasting a &lt;style&gt; tag from the clipboard into a rich text editor, the CSS sanitizer incorrectly rewrites a @namespace rule. This could allow for injection into certain types of websites resulting in data exfiltration. This vulnerability affects Firefox ESR < 68.4 and Firefox < 72.

If an XML file is served with a Content Security Policy and the XML file includes an XSL stylesheet, the Content Security Policy will not be applied to the contents of the XSL stylesheet. If the XSL sheet e.g. includes JavaScript, it would bypass any of the restrictions of the Content Security Policy applied to the XML document. This vulnerability affects Firefox < 72.

Mozilla Firefox before 15.0, Thunderbird before 15.0, and SeaMonkey before 2.12 do not prevent use of the Object.defineProperty method to shadow the location object (aka window.location), which makes it easier for remote attackers to conduct cross-site scripting (XSS) attacks via vectors involving a plugin.