diff --git a/pkgs/development/libraries/ucommon/default.nix b/pkgs/development/libraries/ucommon/default.nix
index 50d8f5e8745b..4d1409324020 100644
--- a/pkgs/development/libraries/ucommon/default.nix
+++ b/pkgs/development/libraries/ucommon/default.nix
@@ -19,6 +19,12 @@ stdenv.mkDerivation rec {
 
   buildInputs = [ pkgconfig ];
 
+  # disable flaky networking test
+  postPatch = ''
+    substituteInPlace test/stream.cpp \
+      --replace 'ifndef UCOMMON_SYSRUNTIME' 'if 0'
+  '';
+
   # ucommon.pc has link time depdendencies on -lssl, -lcrypto, -lz, -lgnutls
   propagatedBuildInputs = [ openssl zlib gnutls ];