diff --git a/pkgs/npdet/default.nix b/pkgs/npdet/default.nix
index bd6c491..c7fb92b 100644
--- a/pkgs/npdet/default.nix
+++ b/pkgs/npdet/default.nix
@@ -64,6 +64,7 @@ stdenv.mkDerivation rec {
 
   cmakeFlags = [
     "-DCMAKE_CXX_STANDARD=17" # match dd4hep
+    "-DPython_FIND_FRAMEWORK=NEVER" # fix for missing sandboxing on GitHub actions
   ];
 
   meta = with lib; {