diff --git a/src/script/standard.h b/src/script/standard.h
index c4b82b4c4..ed85816a3 100644
--- a/src/script/standard.h
+++ b/src/script/standard.h
@@ -48,7 +48,8 @@ static const unsigned int STANDARD_SCRIPT_VERIFY_FLAGS = MANDATORY_SCRIPT_VERIFY
                                                          SCRIPT_VERIFY_STRICTENC |
                                                          SCRIPT_VERIFY_MINIMALDATA |
                                                          SCRIPT_VERIFY_NULLDUMMY |
-                                                         SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_NOPS;
+                                                         SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_NOPS |
+                                                         SCRIPT_VERIFY_CLEANSTACK;
 
 /** For convenience, standard but not mandatory verify flags. */
 static const unsigned int STANDARD_NOT_MANDATORY_VERIFY_FLAGS = STANDARD_SCRIPT_VERIFY_FLAGS & ~MANDATORY_SCRIPT_VERIFY_FLAGS;