diff --git a/pkgs/applications/networking/browsers/firefox/packages.nix b/pkgs/applications/networking/browsers/firefox/packages.nix
index c4e8c0259401..d1b4e92639fe 100644
--- a/pkgs/applications/networking/browsers/firefox/packages.nix
+++ b/pkgs/applications/networking/browsers/firefox/packages.nix
@@ -32,10 +32,10 @@ rec {
 
   firefox-esr-91 = common rec {
     pname = "firefox-esr";
-    version = "91.4.1esr";
+    version = "91.5.0esr";
     src = fetchurl {
       url = "mirror://mozilla/firefox/releases/${version}/source/firefox-${version}.source.tar.xz";
-      sha512 = "1b9f17c4e58e3753f8507754bba93e3b7f76df5b6845d6173719fbdd98b70af2a90242df42fe274217f56d0280e5dbae17962f5b6bf111421260790f770f5337";
+      sha512 = "1712415b6b73c6a21edfefc39eaba5fcbbca54032f78627c0005d291501d16ef4daffb8b9a160d1d5361113ceba04eb5ddb21d903e3dd8d58838aa9596f2d781";
     };
 
     meta = {