A web page could trick a user into setting that site as the default handler for a custom URL protocol. This vulnerability was fixed in Firefox 136, Firefox ESR 128.8, Thunderbird 136, and Thunderbird 128.8.CreditsHafiizhReferenceshttps://bugzilla.mozilla.org/show_bug.cgi?id=1866661https://www.mozilla.org/security/advisories/mfsa2025-14/https://www.mozilla.org/security/advisories/mfsa2025-16/https://www.mozilla.org/security/advisories/mfsa2025-17/https://www.mozilla.org/security/advisories/mfsa2025-18/
