When Responsive Design Mode was enabled, it used references to objects that were previously freed. We presume that with enough effort this could have been exploited to run arbitrary code. This vulnerability affects Firefox ESR < 78.10, Thunderbird < 78.10, and Firefox < 88.

A WebGL framebuffer was not initialized early enough, resulting in memory corruption and an out of bound write. This vulnerability affects Firefox ESR < 78.10, Thunderbird < 78.10, and Firefox < 88.

An attacker may perform a DoS attack to prevent a user from sending encrypted email to a correspondent. If an attacker creates a crafted OpenPGP key with a subkey that has an invalid self signature, and the Thunderbird user imports the crafted key, then Thunderbird may try to use the invalid subkey, but the RNP library rejects it from being used, causing encryption to fail. This vulnerability affects Thunderbird < 78.9.1.

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.

If a Thunderbird user has previously imported Alice's OpenPGP key, and Alice has extended the validity period of her key, but Alice's updated key has not yet been imported, an attacker may send an email containing a crafted version of Alice's key with an invalid subkey, Thunderbird might subsequently attempt to use the invalid subkey, and will fail to send encrypted email to Alice. This vulnerability affects Thunderbird < 78.9.1.

Mozilla developers and community members reported memory safety bugs present in Firefox 86 and Firefox ESR 78.8. 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 ESR < 78.9, Firefox < 87, and Thunderbird < 78.9.

A malicious extension could have opened a popup window lacking an address bar. The title of the popup lacking an address bar should not be fully controllable, but in this situation was. This could have been used to spoof a website and attempt to trick the user into providing credentials. This vulnerability affects Firefox ESR < 78.9, Firefox < 87, and Thunderbird < 78.9.

Using techniques that built on the slipstream research, a malicious webpage could have scanned both an internal network's hosts as well as services running on the user's local machine utilizing WebRTC connections. This vulnerability affects Firefox ESR < 78.9, Firefox < 87, and Thunderbird < 78.9.

A texture upload of a Pixel Buffer Object could have confused the WebGL code to skip binding the buffer used to unpack it, resulting in memory corruption and a potentially exploitable information leak or crash. This vulnerability affects Firefox ESR < 78.9, Firefox < 87, and Thunderbird < 78.9.

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.