diff --git a/pkgs/applications/networking/browsers/firefox/packages.nix b/pkgs/applications/networking/browsers/firefox/packages.nix
index 8dc8b86adb8..497a77967cc 100644
--- a/pkgs/applications/networking/browsers/firefox/packages.nix
+++ b/pkgs/applications/networking/browsers/firefox/packages.nix
@@ -58,10 +58,10 @@ rec {
 
   firefox-esr-78 = common rec {
     pname = "firefox-esr";
-    ffversion = "78.12.0esr";
+    ffversion = "78.13.0esr";
     src = fetchurl {
       url = "mirror://mozilla/firefox/releases/${ffversion}/source/firefox-${ffversion}.source.tar.xz";
-      sha512 = "646eb803e0d0e541773e3111708c7eaa85e784e4bae6e4a77dcecdc617ee29e2e349c9ef16ae7e663311734dd7491aebd904359124dda62672dbc18bfb608f0a";
+      sha512 = "78a5dc8713ab879ebfc3b8fd7a8219844d06f0d897342fdf9a11471633d98e148ff85cf10e561899df4910b94a33b57709b64788df4621a8c0b83eb9a7102cef";
     };
 
     meta = {