diff --git a/nixos/modules/overlays.nix b/nixos/modules/overlays.nix
index 376ffa56b013764934c3e8cecb5b10426728a1b4..4acb9d9ed797d72c0aa9bd381d70d92e84ef5082 100644
--- a/nixos/modules/overlays.nix
+++ b/nixos/modules/overlays.nix
@@ -21,6 +21,8 @@ let
       # And explicitly configure it with our preferred version of Tahoe-LAFS.
       inherit tahoe-lafs;
     };
+
+    pyopenssl = python-self.callPackage ../pkgs/pyopenssl.nix { };
   };
 in
 self: super: {
diff --git a/nixos/pkgs/pyopenssl.nix b/nixos/pkgs/pyopenssl.nix
new file mode 100644
index 0000000000000000000000000000000000000000..7c785bde9f32a5d6781c24434ec70b8fa34a97bd
--- /dev/null
+++ b/nixos/pkgs/pyopenssl.nix
@@ -0,0 +1,9 @@
+{ fetchPypi, pyopenssl }:
+pyopenssl.overrideAttrs (old: {
+  version = "20.0.1";
+  inherit (old) name;
+  src = fetchPypi {
+    inherit name;
+    sha256 = "aeca66338f6de19d1aa46ed634c3b9ae519a64b458f8468aec688e7e3c20f201";
+  };
+})