--- a/tools/clang/tools/scan-build/scan-build
+++ b/tools/clang/tools/scan-build/scan-build
@@ -204,6 +204,12 @@
   else {
     $NewDir = "$Dir/$DateString-$RunNumber";
   }
+
+  # Make sure that the directory does not exist in order to avoid hijack.
+  if (-d $NewDir) {
+      DieDiag("The directory '$NewDir' already exists.\n");
+  }
+
   system 'mkdir','-p',$NewDir;
   return $NewDir;
 }