The fullscreen notification is prematurely hidden when fullscreen is re-requested quickly by the user. This could have been leveraged to perform a potential spoofing attack. This vulnerability affects Firefox < 135 and Thunderbird < 135.CreditsIrvan KurniawanReferenceshttps://bugzilla.mozilla.org/show_bug.cgi?id=1910818https://www.mozilla.org/security/advisories/mfsa2025-07/https://www.mozilla.org/security/advisories/mfsa2025-11/