diff --git a/apache2/re_operators.c b/apache2/re_operators.c
index e27faef4..3d499b41 100644
--- a/apache2/re_operators.c
+++ b/apache2/re_operators.c
@@ -458,6 +458,8 @@ static int msre_op_rsub_execute(modsec_rec *msr, msre_rule *rule, msre_var *var,
             return -1;
         }
 
+        memset(stream_output_data, 0x00, size+1);
+
         var->value_len = size;
         msr->of_stream_changed = 1;
 
@@ -477,6 +479,8 @@ static int msre_op_rsub_execute(modsec_rec *msr, msre_rule *rule, msre_var *var,
             return -1;
         }
 
+        memset(stream_input_data, 0x00, size+1);
+
         var->value_len = size;
         msr->if_stream_changed = 1;