diff --git a/machines/core-services-01/keycloak.nix b/machines/core-services-01/keycloak.nix
index 3890993..b59af18 100644
--- a/machines/core-services-01/keycloak.nix
+++ b/machines/core-services-01/keycloak.nix
@@ -9,7 +9,7 @@ in
 {
   nixpkgs.overlays = [
     (self: super: {
-      zlib = zlib.overrideAttrs (old: {
+      zlib = super.zlib.overrideAttrs (old: {
         patches = old.patches ++ [
           ./fix-crc-computation.patch
         ];