Firefox sometimes ran the onload handler for SVG elements that the DOM sanitizer decided to remove, resulting in JavaScript being executed after pasting attacker-controlled data into a contenteditable element. This vulnerability affects Firefox < 81, Thunderbird < 78.3, and Firefox ESR < 78.3.

Mozilla developers reported memory safety bugs present in Firefox 80 and Firefox ESR 78.2. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 81, Thunderbird < 78.3, and Firefox ESR < 78.3.

Mozilla developers reported memory safety bugs present in Firefox for Android 79. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 80, Firefox ESR < 78.2, Thunderbird < 78.2, and Firefox for Android < 80.

By holding a reference to the eval() function from an about:blank window, a malicious webpage could have gained access to the InstallTrigger object which would allow them to prompt the user to install an extension. Combined with user confusion, this could result in an unintended or malicious extension being installed. This vulnerability affects Firefox < 80, Thunderbird < 78.2, Thunderbird < 68.12, Firefox ESR < 68.12, Firefox ESR < 78.2, and Firefox for Android < 80.

If Firefox is installed to a user-writable directory, the Mozilla Maintenance Service would execute updater.exe from the install location with system privileges. Although the Mozilla Maintenance Service does ensure that updater.exe is signed by Mozilla, the version could have been rolled back to a previous version which would have allowed exploitation of an older bug and arbitrary code execution with System Privileges. *Note: This issue only affected Windows operating systems. Other operating systems are unaffected.*. This vulnerability affects Firefox < 80, Thunderbird < 78.2, Thunderbird < 68.12, Firefox ESR < 68.12, and Firefox ESR < 78.2.

Mozilla developers and community members reported memory safety bugs present in Firefox 78 and Firefox ESR 78.0. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 79, Firefox ESR < 68.11, Firefox ESR < 78.1, Thunderbird < 68.11, and Thunderbird < 78.1.

Mozilla Necko, as used in Firefox, SeaMonkey, and other applications, performs DNS prefetching of domain names contained in links within local HTML documents, which makes it easier for remote attackers to determine the network location of the application's user by logging DNS requests. NOTE: the vendor disputes the significance of this issue, stating "I don't think we necessarily need to worry about that case."

Mozilla Firefox before 3.0.16 and 3.5.x before 3.5.6, and SeaMonkey before 2.0.1, allows remote attackers to spoof an SSL indicator for an http URL or a file URL by setting document.location to an https URL corresponding to a site that responds with a No Content (aka 204) status code and an empty body.

Mozilla Firefox before 3.0.16 and 3.5.x before 3.5.6, and SeaMonkey before 2.0.1, allows remote attackers to send authenticated requests to arbitrary applications by replaying the NTLM credentials of a browser user.

Multiple unspecified vulnerabilities in the JavaScript engine in Mozilla Firefox 3.5.x before 3.5.6, SeaMonkey before 2.0.1, and Thunderbird allow remote attackers to cause a denial of service (memory corruption and application crash) or possibly execute arbitrary code via unknown vectors.

Unspecified vulnerability in the browser engine in Mozilla Firefox before 3.0.16, SeaMonkey before 2.0.1, and Thunderbird allows remote attackers to cause a denial of service (memory corruption and application crash) or possibly execute arbitrary code via unknown vectors.

Multiple unspecified vulnerabilities in the browser engine in Mozilla Firefox 3.5.x before 3.5.6, SeaMonkey before 2.0.1, and Thunderbird allow remote attackers to cause a denial of service (memory corruption and application crash) or possibly execute arbitrary code via unknown vectors.

Heap-based buffer overflow in a regular-expression parser in Mozilla Network Security Services (NSS) before 3.12.3, as used in Firefox, Thunderbird, SeaMonkey, Evolution, Pidgin, and AOL Instant Messenger (AIM), allows remote SSL servers to cause a denial of service (application crash) or possibly execute arbitrary code via a long domain name in the subject's Common Name (CN) field of an X.509 certificate, related to the cert_TestHostName function.

Mozilla Firefox before 3.0.11, Thunderbird, and SeaMonkey do not check content policy before loading a script file into a XUL document, which allows remote attackers to bypass intended access restrictions via a crafted HTML document, as demonstrated by a "web bug" in an e-mail message, or web script or an advertisement in a web page.

Mozilla Firefox before 3.0.9, Thunderbird, and SeaMonkey do not properly implement the Same Origin Policy for (1) XMLHttpRequest, involving a mismatch for a document's principal, and (2) XPCNativeWrapper.toString, involving an incorrect __proto__ scope, which allows remote attackers to conduct cross-site scripting (XSS) attacks and possibly other attacks via a crafted document.

Cross-site scripting (XSS) vulnerability in Mozilla Firefox before 3.0.9, Thunderbird, and SeaMonkey allows remote attackers to inject arbitrary web script or HTML via vectors involving XBL JavaScript bindings and remote stylesheets, as exploited in the wild by a March 2009 eBay listing.

The view-source: URI implementation in Mozilla Firefox before 3.0.9, Thunderbird, and SeaMonkey does not properly implement the Same Origin Policy, which allows remote attackers to (1) bypass crossdomain.xml restrictions and connect to arbitrary web sites via a Flash file; (2) read, create, or modify Local Shared Objects via a Flash file; or (3) bypass unspecified restrictions and render content via vectors involving a jar: URI.

The jar: URI implementation in Mozilla Firefox before 3.0.9, Thunderbird, and SeaMonkey does not follow the Content-Disposition header of the inner URI, which allows remote attackers to conduct cross-site scripting (XSS) attacks and possibly other attacks via an uploaded .jar file with a "Content-Disposition: attachment" designation.

Mozilla Firefox before 2.0.0.17 and 3.x before 3.0.2, Thunderbird before 2.0.0.17, and SeaMonkey before 1.1.12 allow remote attackers to create documents that lack script-handling objects, and execute arbitrary code with chrome privileges, via vectors related to (1) the document.loadBindingDocument function and (2) XSLT.

The nsXMLDocument::OnChannelRedirect function in Mozilla Firefox before 2.0.0.17, Thunderbird before 2.0.0.17, and SeaMonkey before 1.1.12 allows remote attackers to bypass the Same Origin Policy and execute arbitrary JavaScript code via unknown vectors.