diff --git a/pkgs/development/python-modules/fpylll/default.nix b/pkgs/development/python-modules/fpylll/default.nix
index d0ddbf91ceda..b6a0e447ea0a 100644
--- a/pkgs/development/python-modules/fpylll/default.nix
+++ b/pkgs/development/python-modules/fpylll/default.nix
@@ -48,7 +48,10 @@ buildPythonPackage rec {
     fplll
   ];
 
-  propagatedBuildInputs = [ numpy ];
+  propagatedBuildInputs = [
+    numpy
+    cysignals
+  ];
 
   nativeCheckInputs = [ pytestCheckHook ];