CVE-2021-38509

Due to an unusual sequence of attacker-controlled events, a Javascript alert dialog with arbitrary although unstyled contents could be displayed over top an uncontrolled webpage of the attacker's choosing. This vulnerability affects Firefox 94, Thunderbird 91.3, and Firefox ESR 91.3...

Mozilla Firefox has an unspecified vulnerability (CNVD-2021-101164)

Mozilla Firefox is an open source web browser from the Mozilla Foundation. Mozilla Firefox is vulnerable due to an unusual sequence of events controlled by an attacker, and alert can therefore display arbitrary albeit unstyled content on top of an uncontrolled page of the attacker's choice...