Using XMLHttpRequest, an attacker could have identified installed applications by probing error messages for loading external protocols. This vulnerability affects Thunderbird < 91.4.0, Firefox ESR < 91.4.0, and Firefox < 95.Referenceshttps://www.mozilla.org/security/advisories/mfsa2021-53/https://www.mozilla.org/security/advisories/mfsa2021-54/https://www.mozilla.org/security/advisories/mfsa2021-52/https://bugzilla.mozilla.org/show_bug.cgi?id=1723281https://www.debian.org/security/2021/dsa-5026https://lists.debian.org/debian-lts-announce/2021/12/msg00030.htmlhttps://www.debian.org/security/2022/dsa-5034https://lists.debian.org/debian-lts-announce/2022/01/msg00001.htmlhttps://security.gentoo.org/glsa/202202-03https://security.gentoo.org/glsa/202208-14
