Malicious websites could have confused Firefox into showing the wrong origin when asking to launch a program and handling an external URL protocol. This vulnerability affects Firefox ESR < 91.5, Firefox < 96, and Thunderbird < 91.5.
Securitypolicyviolation events could have leaked cross-origin information for frame-ancestors violations. This vulnerability affects Firefox ESR < 91.5, Firefox < 96, and Thunderbird < 91.5.
Mozilla developers Calixte Denizet, Kershaw Chang, Christian Holler, Jason Kratzer, Gabriele Svelto, Tyson Smith, Simon Giesecke, and Steve Fink reported memory safety bugs present in Firefox 95 and Firefox ESR 91.4. 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 < 91.5, Firefox < 96, and Thunderbird < 91.5.
Certain network request objects were freed too early when releasing a network request handle. This could have lead to a use-after-free causing a potentially exploitable crash. This vulnerability affects Firefox ESR < 91.5, Firefox < 96, and Thunderbird < 91.5.
When navigating from inside an iframe while requesting fullscreen access, an attacker-controlled tab could have made the browser unable to leave fullscreen mode. This vulnerability affects Firefox ESR < 91.5, Firefox < 96, and Thunderbird < 91.5.
Constructing audio sinks could have lead to a race condition when playing audio files and closing windows. This could have lead to a use-after-free causing a potentially exploitable crash. This vulnerability affects Firefox ESR < 91.5, Firefox < 96, and Thunderbird < 91.5.
When inserting text while in edit mode, some characters might have lead to out-of-bounds memory access causing a potentially exploitable crash. This vulnerability affects Firefox ESR < 91.5, Firefox < 96, and Thunderbird < 91.5.
Malicious websites could have tricked users into accepting launching a program to handle an external URL protocol. This vulnerability affects Firefox ESR < 91.5, Firefox < 96, and Thunderbird < 91.5.
Applying a CSS filter effect could have accessed out of bounds memory. This could have lead to a heap-buffer-overflow causing a potentially exploitable crash. This vulnerability affects Firefox ESR < 91.5, Firefox < 96, and Thunderbird < 91.5.
It was possible to construct specific XSLT markup that would be able to bypass an iframe sandbox. This vulnerability affects Firefox ESR < 91.5, Firefox < 96, and Thunderbird < 91.5.
When resizing a popup while requesting fullscreen access, the popup would have become unable to leave fullscreen mode. This vulnerability affects Firefox ESR < 91.5, Firefox < 96, and Thunderbird < 91.5.