Vulnerabilities

Mozilla developers Andrew McCreight, Gabriele Svelto, Tom Ritter and the Mozilla Fuzzing Team reported memory safety bugs present in Firefox 99 and Firefox ESR 91.8.

Firefox behaved slightly differently for already known resources when loading CSS resources involving CSS variables.

When reusing existing popups Firefox would have allowed them to cover the fullscreen notification UI, which could have enabled browser spoofing attacks.

The parent process would not properly check whether the Speech Synthesis feature is enabled, when receiving instructions from a child process.

Requests initiated through reader mode did not properly omit cookies with a SameSite attribute.

An improper implementation of the new iframe sandbox keyword <code>allow-top-navigation-by-user-activation</code> could lead to script execution without <code>allow-scripts</code> being present.

Documents in deeply-nested cross-origin browsing contexts could have obtained permissions granted to the top-level origin, bypassing the existing prompt and wrongfully inheriting the top-level permissions.

When viewing an email message A, which contains an attached message B, where B is encrypted or digitally signed or both, Thunderbird may show an incorrect encryption or signature status.