diff --git a/pkgs/applications/networking/browsers/firefox/common.nix b/pkgs/applications/networking/browsers/firefox/common.nix
index 85b43b387023..6c66c3ef8f5b 100644
--- a/pkgs/applications/networking/browsers/firefox/common.nix
+++ b/pkgs/applications/networking/browsers/firefox/common.nix
@@ -11,6 +11,7 @@
 , icu67, libpng, jemalloc, glib
 , autoconf213, which, gnused, cargo, rustc
 , rust-cbindgen, nodejs, nasm, fetchpatch
+, gnum4
 , debugBuild ? false
 
 ### optionals
@@ -147,6 +148,7 @@ buildStdenv.mkDerivation ({
   ++ lib.optional  ltoSupport llvmPackages.libunwind
   ++ lib.optionals waylandSupport [ libxkbcommon ]
   ++ lib.optionals pipewireSupport [ pipewire ]
+  ++ lib.optionals (lib.versionAtLeast ffversion "82") [ gnum4 ]
   ++ lib.optionals buildStdenv.isDarwin [ CoreMedia ExceptionHandling Kerberos
                                           AVFoundation MediaToolbox CoreLocation
                                           Foundation libobjc AddressBook cups ];
diff --git a/pkgs/applications/networking/browsers/firefox/packages.nix b/pkgs/applications/networking/browsers/firefox/packages.nix
index 115588c226f4..79391887608c 100644
--- a/pkgs/applications/networking/browsers/firefox/packages.nix
+++ b/pkgs/applications/networking/browsers/firefox/packages.nix
@@ -7,10 +7,10 @@ in
 rec {
   firefox = common rec {
     pname = "firefox";
-    ffversion = "81.0.2";
+    ffversion = "82.0";
     src = fetchurl {
       url = "mirror://mozilla/firefox/releases/${ffversion}/source/firefox-${ffversion}.source.tar.xz";
-      sha512 = "1szsj7rwpn7ggiavvnc38a75ip0r3p5bgr2kvy2hq7519abzmr3z49jg4alpsy1ndkfylvh28zjw9h5xys0bvs40f33ps90j60z8gla";
+      sha512 = "3lbvlb6yggd5v0pkr0x6j350jc5dpclqz7bv4i06r97a5ijdgfc7c6y605966hvw24v17byxr120xc7a39ikl1wnls7a9gyzyqcwyw8";
     };
 
     patches = [
@@ -36,10 +36,10 @@ rec {
 
   firefox-esr-78 = common rec {
     pname = "firefox-esr";
-    ffversion = "78.3.1esr";
+    ffversion = "78.4.0esr";
     src = fetchurl {
       url = "mirror://mozilla/firefox/releases/${ffversion}/source/firefox-${ffversion}.source.tar.xz";
-      sha512 = "10a7xfp396n81aj17fbl1b1jr8gbn5ild2ig5cfz6r5ff3wfbjs3x0iqrlwqnjfdqq2pw19k2yrv91iwymd8jwjj4p35xsfivgn0a0n";
+      sha512 = "13640ssp1nq9dsfv8jqfw2paqk3wzwc4r47mvbhb4l9h990gzzb2chhlcjq066b7r3q9s0nq3iyk847vzi7z1yvhrhsnzfgk9g9gpnr";
     };
 
     patches = [