diff --git a/pkgs/applications/networking/browsers/firefox/packages.nix b/pkgs/applications/networking/browsers/firefox/packages.nix
index 0ec96401ecf..23126d1eec0 100644
--- a/pkgs/applications/networking/browsers/firefox/packages.nix
+++ b/pkgs/applications/networking/browsers/firefox/packages.nix
@@ -59,10 +59,10 @@ rec {
 
   firefox-esr-78 = common rec {
     pname = "firefox-esr";
-    ffversion = "78.14.0esr";
+    ffversion = "78.15.0esr";
     src = fetchurl {
       url = "mirror://mozilla/firefox/releases/${ffversion}/source/firefox-${ffversion}.source.tar.xz";
-      sha512 = "5d5e4b1197f87b458a8ab14a62701fa0f3071e9facbb4fba71a64ef69abf31edbb4c5efa6c20198de573216543b5289270b5929c6e917f01bb165ce8c139c1ac";
+      sha512 = "ac3de735b246ce4f0e1619cd2664321ffa374240ce6843e785d79a350dc30c967996bbcc5e3b301cb3d822ca981cbea116758fc4122f1738d75ddfd1165b6378";
     };
 
     meta = {