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.

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.

Microsoft introduced a new feature in Windows 10 known as Cloud Clipboard which, if enabled, will record data copied to the clipboard to the cloud, and make it available on other computers in certain scenarios. Applications that wish to prevent copied data from being recorded in Cloud History must use specific clipboard formats; and Firefox before versions 94 and ESR 91.3 did not implement them. This could have caused sensitive data to be recorded to a user's Microsoft account. *This bug only affects Firefox for Windows 10+ with Cloud Clipboard enabled. Other operating systems are unaffected.*. This vulnerability affects Firefox < 94, Thunderbird < 91.3, and Firefox ESR < 91.3.

When interacting with an HTML input element's file picker dialog with webkitdirectory set, a use-after-free could have resulted, leading to memory corruption and a potentially exploitable crash. This vulnerability affects Firefox < 94, Thunderbird < 91.3, and Firefox ESR < 91.3.

The iframe sandbox rules were not correctly applied to XSLT stylesheets, allowing an iframe to bypass restrictions such as executing scripts or navigating the top-level frame. This vulnerability affects Firefox < 94, Thunderbird < 91.3, and Firefox ESR < 91.3.

Mozilla developers reported memory safety bugs present in Firefox 92 and Firefox ESR 91.1. 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 < 93, Thunderbird < 91.2, and Firefox ESR < 91.2.

Mozilla developers reported memory safety bugs present in Firefox 92 and Firefox ESR 91.1. 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 Thunderbird < 78.15, Thunderbird < 91.2, Firefox ESR < 91.2, Firefox ESR < 78.15, and Firefox < 93.

Mozilla developers reported memory safety bugs present in Firefox 92. 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 < 93.

During process shutdown, a document could have caused a use-after-free of a languages service object, leading to memory corruption and a potentially exploitable crash. This vulnerability affects Firefox < 93, Thunderbird < 91.2, and Firefox ESR < 91.2.

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.

During operations on MessageTasks, a task may have been removed while it was still scheduled, resulting in memory corruption and a potentially exploitable crash. This vulnerability affects Thunderbird < 78.15, Thunderbird < 91.2, Firefox ESR < 91.2, Firefox ESR < 78.15, and Firefox < 93.

Out of bounds write in ANGLE in Google Chrome prior to 91.0.4472.101 allowed a remote attacker to potentially perform out of bounds memory access via a crafted HTML page.

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.