diff --git a/scripts/compare-diffs.sh b/scripts/compare-diffs.sh
index da67135..5cf9095 100755
--- a/scripts/compare-diffs.sh
+++ b/scripts/compare-diffs.sh
@@ -2,8 +2,8 @@
 
 set -e
 
-PLUGIN_OUTPUT=$(mktemp -d -t plugin_)
-GETH_OUTPUT=$(mktemp -d -t geth_)
+PLUGIN_OUTPUT=$(mktemp -d -t plugin_XXXX)
+GETH_OUTPUT=$(mktemp -d -t geth_XXXX)
 
 ./dumpdiff.plugeth $PLUGIN_OUTPUT
 ./dumpdiff.geth $GETH_OUTPUT