diff --git a/Source/script.cpp b/Source/script.cpp
index 18335c33..4021801b 100644
--- a/Source/script.cpp
+++ b/Source/script.cpp
@@ -1037,7 +1037,7 @@ int CEXEBuild::doCommand(int which_token, LineParser &line)
 #else
         char t[] = "/tmp/makensisXXXXXX";
 
-        mode_t old_umask = umask(0600);
+        mode_t old_umask = umask(0077);
 
         int fd = mkstemp(t);
         if (fd == -1) {