diff --git a/apache2/re_actions.c b/apache2/re_actions.c
index 4a922d27..febc4759 100644
--- a/apache2/re_actions.c
+++ b/apache2/re_actions.c
@@ -1455,8 +1455,9 @@ static apr_status_t msre_action_sanitizeArg_execute(modsec_rec *msr, apr_pool_t
     for (i = 0; i < tarr->nelts; i++) {
         msc_arg *arg = (msc_arg *)telts[i].val;
 
-        if (strcasecmp(sargname, arg->name) == 0) {
+        if (arg->marked_for_sanitization == 0 && strcasecmp(sargname, arg->name) == 0) {
             apr_table_addn(msr->arguments_to_sanitize, arg->name, (void *)arg);
+            arg->marked_for_sanitization = 1;
         }
     }