diff --git a/pkgs/applications/networking/browsers/firefox/common.nix b/pkgs/applications/networking/browsers/firefox/common.nix
index 62f525a76959..aadbb32d6e02 100644
--- a/pkgs/applications/networking/browsers/firefox/common.nix
+++ b/pkgs/applications/networking/browsers/firefox/common.nix
@@ -27,7 +27,6 @@
 
 # build time
 , autoconf
-, cargo
 , dump_syms
 , makeWrapper
 , mimalloc
@@ -37,7 +36,8 @@
 , pkgsCross # wasm32 rlbox
 , python3
 , runCommand
-, rustc
+, rustPackages_1_69
+, rustPackages_1_70
 , rust-cbindgen
 , rustPlatform
 , unzip
@@ -147,6 +147,13 @@ assert pipewireSupport -> !waylandSupport || !webrtcSupport -> throw "${pname}:
 let
   inherit (lib) enableFeature;
 
+  rustPackages = if lib.versionAtLeast version "120" then
+    rustPackages_1_70
+  else
+    rustPackages_1_69;
+
+  inherit (rustPackages) cargo rustc;
+
   # Target the LLVM version that rustc is built with for LTO.
   llvmPackages0 = rustc.llvmPackages;
   llvmPackagesBuildBuild0 = pkgsBuildBuild.rustc.llvmPackages;
@@ -490,6 +497,9 @@ buildStdenv.mkDerivation ({
 
   preBuild = ''
     cd mozobj
+  '' + lib.optionalString (lib.versionAtLeast version "120") ''
+    # https://bugzilla.mozilla.org/show_bug.cgi?id=1864083
+    export NIX_CFLAGS_COMPILE="$NIX_CFLAGS_COMPILE $(pkg-config dbus-1 --cflags)"
   '';
 
   postBuild = ''
diff --git a/pkgs/applications/networking/browsers/firefox/packages.nix b/pkgs/applications/networking/browsers/firefox/packages.nix
index 8f3ac6f5859f..83fafbe1280e 100644
--- a/pkgs/applications/networking/browsers/firefox/packages.nix
+++ b/pkgs/applications/networking/browsers/firefox/packages.nix
@@ -29,11 +29,11 @@
 
   firefox-beta = buildMozillaMach rec {
     pname = "firefox-beta";
-    version = "119.0b9";
+    version = "120.0b9";
     applicationName = "Mozilla Firefox Beta";
     src = fetchurl {
       url = "mirror://mozilla/firefox/releases/${version}/source/firefox-${version}.source.tar.xz";
-      sha512 = "11d07474e3ca72a4e2f60053882e09a215e0d29d6830d0cd41447bb67370118356090af7adcbacd7703ad9fcdda83c9f909419c86b8f3bf2eacd9ca3d3aa3f54";
+      sha512 = "7ac5562ce393ea84663eac5c6ee1a0ca527ff4a8a9ec6aaaef37213ff071076846949e80af21d95ec8e32d3cbc740b772a9d7cc54965b7bbc8e015da22ae927f";
     };
 
     meta = {
@@ -56,12 +56,12 @@
 
   firefox-devedition = (buildMozillaMach rec {
     pname = "firefox-devedition";
-    version = "119.0b9";
+    version = "120.0b9";
     applicationName = "Mozilla Firefox Developer Edition";
     branding = "browser/branding/aurora";
     src = fetchurl {
       url = "mirror://mozilla/devedition/releases/${version}/source/firefox-${version}.source.tar.xz";
-      sha512 = "ce3e2adb3171aa05c7af3b7a4ea25eaafbc109c522b90e26aad577192a0902000fb7d705fa5707a9a7d0be2ab1c0cddc5a98abbe6549e1377c0a1d765bda62eb";
+      sha512 = "07bf1a58550e70c683719adef55fa3d1ee06876e0cb086c28242879c683269c4aa784b1dce639218b3ad24a546192088fe5224a52e13a0086f205ec5470e2428";
     };
 
     meta = {
diff --git a/pkgs/development/compilers/rust/1_70.nix b/pkgs/development/compilers/rust/1_70.nix
new file mode 100644
index 000000000000..9025adacfe74
--- /dev/null
+++ b/pkgs/development/compilers/rust/1_70.nix
@@ -0,0 +1,63 @@
+# New rust versions should first go to staging.
+# Things to check after updating:
+# 1. Rustc should produce rust binaries on x86_64-linux, aarch64-linux and x86_64-darwin:
+#    i.e. nix-shell -p fd or @GrahamcOfBorg build fd on github
+#    This testing can be also done by other volunteers as part of the pull
+#    request review, in case platforms cannot be covered.
+# 2. The LLVM version used for building should match with rust upstream.
+#    Check the version number in the src/llvm-project git submodule in:
+#    https://github.com/rust-lang/rust/blob/<version-tag>/.gitmodules
+# 3. Firefox and Thunderbird should still build on x86_64-linux.
+
+{ stdenv, lib
+, buildPackages
+, newScope, callPackage
+, CoreFoundation, Security, SystemConfiguration
+, pkgsBuildTarget, pkgsBuildBuild, pkgsBuildHost
+, makeRustPlatform
+, llvmPackages_11
+, llvmPackages_15, llvm_15
+} @ args:
+
+import ./default.nix {
+  rustcVersion = "1.70.0";
+  rustcSha256 = "sha256-sr+uAAt6UEDk7Eu8UKCfIVSBkMt1cLDtdzWDaEE70nw=";
+
+  llvmSharedForBuild = pkgsBuildBuild.llvmPackages_15.libllvm.override { enableSharedLibraries = true; };
+  llvmSharedForHost = pkgsBuildHost.llvmPackages_15.libllvm.override { enableSharedLibraries = true; };
+  llvmSharedForTarget = pkgsBuildTarget.llvmPackages_15.libllvm.override { enableSharedLibraries = true; };
+
+  llvmBootstrapForDarwin = llvmPackages_11;
+
+  # For use at runtime
+  llvmShared = llvm_15.override { enableSharedLibraries = true; };
+
+  # Expose llvmPackages used for rustc from rustc via passthru for LTO in Firefox
+  llvmPackages = llvmPackages_15;
+
+  # Note: the version MUST be one version prior to the version we're
+  # building
+  bootstrapVersion = "1.69.0";
+
+  # fetch hashes by running `print-hashes.sh ${bootstrapVersion}`
+  bootstrapHashes = {
+    i686-unknown-linux-gnu = "08b2b4f58c0861f40ae159c39cc12f6d41b6858e04a43c6c0aeb36707e2971d0";
+    x86_64-unknown-linux-gnu = "2ca4a306047c0b8b4029c382910fcbc895badc29680e0332c9df990fd1c70d4f";
+    x86_64-unknown-linux-musl = "071cb04819b15d8801584a1395b28d0472ce99c0e716296e3c0bb4e6318cf171";
+    arm-unknown-linux-gnueabihf = "64c82735b4e5606af61be0d01317da436a9590b969e503cdbd19e24636e15845";
+    armv7-unknown-linux-gnueabihf = "a509f02d910041c97847e2ccc4ee908c761b7dc5b3c4715922d2b1c573a09675";
+    aarch64-unknown-linux-gnu = "88af5aa7a40c8f1b40416a1f27de8ffbe09c155d933f69d3e109c0ccee92353b";
+    aarch64-unknown-linux-musl = "76aaf3e4fd7b552feb2d70752c43896a960a2a7c940002f58a5c3f03d2b3c862";
+    x86_64-apple-darwin = "9818dab2c3726d63dfbfde12c9273e62e484ef6d6f6e05a6431a3e089c335454";
+    aarch64-apple-darwin = "36228cac303298243fb84235db87a5ecf2af49db28585a82af091caefd598677";
+    powerpc64le-unknown-linux-gnu = "8ef68b77971c079dbe23b54a2cfb52da012873d96399c424bc223635306e9a58";
+    riscv64gc-unknown-linux-gnu = "e1976bf7d0edb7e7789a1ad7ff8086fdb5306a932650fa8182a5d009883fa6c5";
+    mips64el-unknown-linux-gnuabi64 = "c4bf3043451d6122a3845db825cbe35b5ca61a44659a00004f6cca1299ad9d72";
+  };
+
+  selectRustPackage = pkgs: pkgs.rust_1_70;
+
+  rustcPatches = [ ];
+}
+
+(builtins.removeAttrs args [ "pkgsBuildHost" "llvmPackages_11" "llvmPackages_15" "llvm_15"])
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index 65546962041f..2fc30fac2a3b 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -16319,6 +16319,10 @@ with pkgs;
     inherit (darwin.apple_sdk.frameworks) CoreFoundation Security SystemConfiguration;
     llvm_15 = llvmPackages_15.libllvm;
   };
+  rust_1_70 = callPackage ../development/compilers/rust/1_70.nix {
+    inherit (darwin.apple_sdk.frameworks) CoreFoundation Security SystemConfiguration;
+    llvm_15 = llvmPackages_15.libllvm;
+  };
   rust = rust_1_69;
 
   mrustc = callPackage ../development/compilers/mrustc { };
@@ -16328,6 +16332,7 @@ with pkgs;
   };
 
   rustPackages_1_69 = rust_1_69.packages.stable;
+  rustPackages_1_70 = rust_1_70.packages.stable;
   rustPackages = rustPackages_1_69;
 
   inherit (rustPackages) cargo cargo-auditable cargo-auditable-cargo-wrapper clippy rustc rustPlatform;