diff --git a/pkgs/tools/networking/nbd/default.nix b/pkgs/tools/networking/nbd/default.nix
index c136328d031..6478a15aa1a 100644
--- a/pkgs/tools/networking/nbd/default.nix
+++ b/pkgs/tools/networking/nbd/default.nix
@@ -1,11 +1,11 @@
 { lib, stdenv, fetchurl, pkg-config, glib, which }:
 
 stdenv.mkDerivation rec {
-  name = "nbd-3.20";
+  name = "nbd-3.21";
 
   src = fetchurl {
     url = "mirror://sourceforge/nbd/${name}.tar.xz";
-    sha256 = "1kfnyx52nna2mnw264njk1dl2zc8m78sz031yp65mbmpi99v7qg0";
+    sha256 = "sha256-52iK852Rczu80tsIBixE/lA9AE5RUodAE5xEr/amvvk=";
   };
 
   buildInputs = [ glib ]