diff --git a/ext/ldap/ldap.c b/ext/ldap/ldap.c
index 7ddddfbbc86..446db903958 100644
--- a/ext/ldap/ldap.c
+++ b/ext/ldap/ldap.c
@@ -2759,7 +2759,7 @@ PHP_FUNCTION(ldap_modify_batch)
 
 	/* for each modification */
 	zend_ulong modification_index = 0;
-	ZEND_HASH_FOREACH_NUM_KEY_VAL(modifications, modification_index, modification_zv) {
+	ZEND_HASH_FOREACH_VAL(modifications, modification_zv) {
 		ldap_mods[modification_index] = safe_emalloc(1, sizeof(LDAPMod), 0);
 
 		zval *attrib_zv = zend_hash_str_find_deref(Z_ARRVAL_P(modification_zv), LDAP_MODIFY_BATCH_ATTRIB, strlen(LDAP_MODIFY_BATCH_ATTRIB));
@@ -2822,6 +2822,8 @@ PHP_FUNCTION(ldap_modify_batch)
 			/* NULL-terminate values */
 			ldap_mods[modification_index]->mod_bvalues[num_modification_values] = NULL;
 		}
+
+		modification_index++;
 	} ZEND_HASH_FOREACH_END();
 
 	/* NULL-terminate modifications */
diff --git a/ext/ldap/tests/ldap_modify_batch_error.phpt b/ext/ldap/tests/ldap_modify_batch_error.phpt
index bce62cafb27..0ac093b4a03 100644
--- a/ext/ldap/tests/ldap_modify_batch_error.phpt
+++ b/ext/ldap/tests/ldap_modify_batch_error.phpt
@@ -59,6 +59,16 @@ $mods = array(
     )
 );
 
+var_dump(ldap_modify_batch($link, "dc=my-domain,$base", $mods));
+
+// high key with invalid attribute type
+$mods = [
+    99999 => [
+        "attrib"  => "weirdAttribute",
+        "modtype" => LDAP_MODIFY_BATCH_ADD,
+        "values"  => ["value1"],
+    ],
+];
 var_dump(ldap_modify_batch($link, "dc=my-domain,$base", $mods));
 ?>
 --CLEAN--
@@ -81,3 +91,6 @@ bool(false)
 
 Warning: ldap_modify_batch(): Batch Modify: Undefined attribute type in %s on line %d
 bool(false)
+
+Warning: ldap_modify_batch(): Batch Modify: Undefined attribute type in %s on line %d
+bool(false)