diff --git a/pkgs/development/ocaml-modules/bls12-381-signature/default.nix b/pkgs/development/ocaml-modules/bls12-381-signature/default.nix
index cfb03c5e6d0b..1ba61c1c35a5 100644
--- a/pkgs/development/ocaml-modules/bls12-381-signature/default.nix
+++ b/pkgs/development/ocaml-modules/bls12-381-signature/default.nix
@@ -8,11 +8,11 @@
   integers_stubs_js,
 }:
 
-buildDunePackage rec {
+buildDunePackage (finalAttrs: {
   pname = "bls12-381-signature";
   version = "1.0.0";
   src = fetchzip {
-    url = "https://gitlab.com/nomadic-labs/cryptography/ocaml-${pname}/-/archive/${version}/ocaml-bls12-381-signature-${version}.tar.bz2";
+    url = "https://gitlab.com/nomadic-labs/cryptography/ocaml-bls12-381-signature/-/archive/${finalAttrs.version}/ocaml-bls12-381-signature-${finalAttrs.version}.tar.bz2";
     sha256 = "sha256-KaUpAT+BWxmUP5obi4loR9vVUeQmz3p3zG3CBolUuL4=";
   };
 
@@ -36,4 +36,4 @@ buildDunePackage rec {
     homepage = "https://gitlab.com/nomadic-labs/cryptography/ocaml-bls12-381-signature";
     maintainers = [ lib.maintainers.ulrikstrid ];
   };
-}
+})