If a user downloaded a file lacking an extension on Windows, and then "Open"-ed it from the downloads panel, if there was an executable file in the downloads directory with the same name but with an executable extension (such as .bat or .exe) that executable would have been launched instead. *Note: This issue only affected Windows operating systems. Other operating systems are unaffected.*. This vulnerability affects Firefox < 84, Thunderbird < 78.6, and Firefox ESR < 78.6.

When an extension with the proxy permission registered to receive <all_urls>, the proxy.onRequest callback was not triggered for view-source URLs. While web content cannot navigate to such URLs, a user opening View Source could have inadvertently leaked their IP address. This vulnerability affects Firefox < 84, Thunderbird < 78.6, and Firefox ESR < 78.6.

When a user typed a URL in the address bar or the search bar and quickly hit the enter key, a website could sometimes capture that event and then redirect the user before navigation occurred to the desired, entered address. To construct a convincing spoof the attacker would have had to guess what the user was typing, perhaps by suggesting it. This vulnerability affects Firefox < 84.

Using techniques that built on the slipstream research, a malicious webpage could have exposed both an internal network's hosts as well as services running on the user's local machine. This vulnerability affects Firefox < 84, Thunderbird < 78.6, and Firefox ESR < 78.6.

When a HTTPS pages was embedded in a HTTP page, and there was a service worker registered for the former, the service worker could have intercepted the request for the secure page despite the iframe not being a secure context due to the (insecure) framing. This vulnerability affects Firefox < 84.

When flex-basis was used on a table wrapper, a StyleGenericFlexBasis object could have been incorrectly cast to the wrong type. This resulted in a heap user-after-free, memory corruption, and a potentially exploitable crash. This vulnerability affects Firefox < 84, Thunderbird < 78.6, and Firefox ESR < 78.6.

Certain input to the CSS Sanitizer confused it, resulting in incorrect components being removed. This could have been used as a sanitizer bypass. This vulnerability affects Firefox < 84, Thunderbird < 78.6, and Firefox ESR < 78.6.

The lifecycle of IPC Actors allows managed actors to outlive their manager actors; and the former must ensure that they are not attempting to use a dead actor they have a reference to. Such a check was omitted in WebGL, resulting in a use-after-free and a potentially exploitable crash. This vulnerability affects Firefox < 84.

Certain blit values provided by the user were not properly constrained leading to a heap buffer overflow on some video drivers. This vulnerability affects Firefox < 84, Thunderbird < 78.6, and Firefox ESR < 78.6.

The HTTP/2 protocol does not consider the role of the TCP congestion window in providing information about content length, which makes it easier for remote attackers to obtain cleartext data by leveraging a web-browser configuration in which third-party cookies are sent, aka a "HEIST" attack.

The HTTPS protocol does not consider the role of the TCP congestion window in providing information about content length, which makes it easier for remote attackers to obtain cleartext data by leveraging a web-browser configuration in which third-party cookies are sent, aka a "HEIST" attack.

Cross-site scripting (XSS) vulnerability in clickstream.js in Y! Toolbar plugin for FireFox 3.1.0.20130813024103 for Mac, and 2.5.9.2013418100420 for Windows, allows remote attackers to inject arbitrary web script or HTML via a crafted URL that is stored by the victim.

Unspecified vulnerability in Oracle Java SE 6u65 and Java SE 7u45, when running on Firefox, allows remote attackers to affect confidentiality, integrity, and availability via unknown vectors related to Deployment.

Cross-site scripting (XSS) vulnerability in the bulletin-board component in Cybozu Garoon before 3.7.2, when Internet Explorer or Firefox is used, allows remote authenticated users to inject arbitrary web script or HTML via unspecified vectors.

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 note 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 the Space function in Cybozu Garoon before 3.7.0, when Firefox is used, allows remote attackers to inject arbitrary web script or HTML via unspecified vectors.

Unspecified vulnerability in the Java Runtime Environment (JRE) component in Oracle Java SE 7 Update 10 and Update 11, when running on Windows using Internet Explorer, Firefox, Opera, and Google Chrome, allows remote attackers to bypass the "Very High" security level of the Java Control Panel and execute unsigned Java code without prompting the user via unknown vectors, aka "Issue 53" and the "Java Security Slider" vulnerability.

The SPDY protocol 3 and earlier, as used in Mozilla Firefox, Google Chrome, and other products, can perform TLS encryption of compressed data without properly obfuscating the length of the unencrypted data, which allows man-in-the-middle attackers to obtain plaintext HTTP headers by observing length differences during a series of guesses in which a string in an HTTP request potentially matches an unknown string in an HTTP header, aka a "CRIME" attack.