diff --git a/pkgs/development/tools/analysis/spin/default.nix b/pkgs/development/tools/analysis/spin/default.nix
index 6da6bd4b4f9..48ba6379a0c 100644
--- a/pkgs/development/tools/analysis/spin/default.nix
+++ b/pkgs/development/tools/analysis/spin/default.nix
@@ -7,15 +7,15 @@ let
 
 in stdenv.mkDerivation rec {
   name = "spin-${version}";
-  version = "6.4.5";
+  version = "6.4.6";
   url-version = stdenv.lib.replaceChars ["."] [""] version;
 
   src = fetchurl {
     # The homepage is behind CloudFlare anti-DDoS protection, which blocks cURL.
     # Dropbox mirror from developers:
     # https://www.dropbox.com/sh/fgzipzp4wpo3qc1/AADZPqS4aoR-pjNF6OQXRLQHa
-    url = "https://www.dropbox.com/sh/fgzipzp4wpo3qc1/AAANRpxsSyWC7iHZB-XgBwJFa/spin645.tar.gz?raw=1";
-    sha256 = "0x8qnwm2xa8f176c52mzpvnfzglxs6xgig7bcgvrvkb3xf114224";
+    url = "https://www.dropbox.com/sh/fgzipzp4wpo3qc1/AAA-vBeJ7xty-CDZgk7OB58Ta/spin646.tar.gz?raw=1";
+    sha256 = "1n33qzlb7g30vhr5yxssw210b2m0242y9j21c7fqpn9z6b0rbhjp";
   };
 
   nativeBuildInputs = [ makeWrapper ];