diff --git a/pkgs/tools/networking/curl/default.nix b/pkgs/tools/networking/curl/default.nix
index 0fea977cd05..16e8835da7d 100644
--- a/pkgs/tools/networking/curl/default.nix
+++ b/pkgs/tools/networking/curl/default.nix
@@ -7,6 +7,7 @@
 
 assert zlibSupport -> zlib != null;
 assert sslSupport -> openssl != null;
+assert scpSupport -> libssh2 != null;
 
 stdenv.mkDerivation rec {
   name = "curl-7.21.0";