diff --git a/services/murmur.nix b/services/murmur.nix
index 68e51c8..77a30ed 100644
--- a/services/murmur.nix
+++ b/services/murmur.nix
@@ -40,5 +40,5 @@ in
   };
 
   # set ACLs so that the murmur user can read the certificates
-  security.acme.certs."mumble.hacc.space".postRun = "setfacl -Rm u:murmur:rX /var/lib/acme/mumble.hacc.space";
+  security.acme.certs."mumble.hacc.space".postRun = "${pkgs.acl}/bin/setfacl -Rm u:murmur:rX /var/lib/acme/mumble.hacc.space";
 }