diff --git a/pkgs/development/interpreters/spidermonkey/91.nix b/pkgs/development/interpreters/spidermonkey/91.nix
index c1e647deb70..f1f5c7bb56a 100644
--- a/pkgs/development/interpreters/spidermonkey/91.nix
+++ b/pkgs/development/interpreters/spidermonkey/91.nix
@@ -19,11 +19,11 @@
 
 stdenv.mkDerivation rec {
   pname = "spidermonkey";
-  version = "91.8.0";
+  version = "91.9.0";
 
   src = fetchurl {
     url = "mirror://mozilla/firefox/releases/${version}esr/source/firefox-${version}esr.source.tar.xz";
-    sha512 = "edea2c7d4d3d0322091b20b623019ef041090d9f89f33c8e3140f66a54624261f278257393db70d2038154de8ee02da0bee6ecf85c281f3558338da71fc173c3";
+    sha512 = "fd69d489429052013d2c1b8b766a47920ecee62f0688505758f593b27ae66d6343b9107163749406251aedebdf836147e4d562415a811b04d7ab2ae31e32f133";
   };
 
   outputs = [ "out" "dev" ];