diff --git a/pkgs/development/interpreters/spidermonkey/91.nix b/pkgs/development/interpreters/spidermonkey/91.nix
index f1f5c7bb56a..ee8557f49c9 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 = "91.9.0";
+  version = "91.9.1";
 
   src = fetchurl {
     url = "mirror://mozilla/firefox/releases/${version}esr/source/firefox-${version}esr.source.tar.xz";
-    sha512 = "fd69d489429052013d2c1b8b766a47920ecee62f0688505758f593b27ae66d6343b9107163749406251aedebdf836147e4d562415a811b04d7ab2ae31e32f133";
+    sha512 = "d432d559f2c5f4b0bc66a755db7d61585e24a727cd8d18630854b3fb8633d54baf61ed65b580345b13d52b66288aa15ca8ca5cfcde8231e88108241f0b007683";
   };
 
   outputs = [ "out" "dev" ];