It was possible to move the cursor using pointerlock from an iframe. This allowed moving the cursor outside of the viewport and the Firefox window. This vulnerability affects Firefox < 128 and Thunderbird < 128.
{ "binaries": [ { "binary_name": "firefox", "binary_version": "128.0+build2-0ubuntu0.20.04.1" }, { "binary_name": "firefox-dev", "binary_version": "128.0+build2-0ubuntu0.20.04.1" }, { "binary_name": "firefox-geckodriver", "binary_version": "128.0+build2-0ubuntu0.20.04.1" }, { "binary_name": "firefox-mozsymbols", "binary_version": "128.0+build2-0ubuntu0.20.04.1" } ], "availability": "No subscription required" }