diff --git a/ext/enchant/enchant.c b/ext/enchant/enchant.c
index 0f0ce3d1201..9a905db2639 100644
--- a/ext/enchant/enchant.c
+++ b/ext/enchant/enchant.c
@@ -332,7 +332,7 @@ PHP_FUNCTION(enchant_broker_set_dict_path)
 	char *value;
 	size_t value_len;
 
-	if (zend_parse_parameters(ZEND_NUM_ARGS(), "Ols", &broker, enchant_broker_ce, &dict_type, &value, &value_len) == FAILURE) {
+	if (zend_parse_parameters(ZEND_NUM_ARGS(), "Olp", &broker, enchant_broker_ce, &dict_type, &value, &value_len) == FAILURE) {
 		RETURN_THROWS();
 	}
 
@@ -429,7 +429,7 @@ PHP_FUNCTION(enchant_broker_request_dict)
 	char *tag;
 	size_t taglen;
 
-	if (zend_parse_parameters(ZEND_NUM_ARGS(), "Os", &broker, enchant_broker_ce, &tag, &taglen) == FAILURE) {
+	if (zend_parse_parameters(ZEND_NUM_ARGS(), "Op", &broker, enchant_broker_ce, &tag, &taglen) == FAILURE) {
 		RETURN_THROWS();
 	}
 
@@ -523,7 +523,7 @@ PHP_FUNCTION(enchant_broker_dict_exists)
 	size_t taglen;
 	enchant_broker * pbroker;
 
-	if (zend_parse_parameters(ZEND_NUM_ARGS(), "Os", &broker, enchant_broker_ce,  &tag, &taglen) == FAILURE) {
+	if (zend_parse_parameters(ZEND_NUM_ARGS(), "Op", &broker, enchant_broker_ce,  &tag, &taglen) == FAILURE) {
 		RETURN_THROWS();
 	}
 
@@ -548,7 +548,7 @@ PHP_FUNCTION(enchant_broker_set_ordering)
 	size_t ptaglen;
 	enchant_broker * pbroker;
 
-	if (zend_parse_parameters(ZEND_NUM_ARGS(), "Oss", &broker, enchant_broker_ce, &ptag, &ptaglen, &pordering, &porderinglen) == FAILURE) {
+	if (zend_parse_parameters(ZEND_NUM_ARGS(), "Opp", &broker, enchant_broker_ce, &ptag, &ptaglen, &pordering, &porderinglen) == FAILURE) {
 		RETURN_THROWS();
 	}
 
@@ -586,7 +586,7 @@ PHP_FUNCTION(enchant_dict_quick_check)
 	size_t wordlen;
 	enchant_dict *pdict;
 
-	if (zend_parse_parameters(ZEND_NUM_ARGS(), "Os|z", &dict, enchant_dict_ce, &word, &wordlen, &sugg) == FAILURE) {
+	if (zend_parse_parameters(ZEND_NUM_ARGS(), "Op|z", &dict, enchant_dict_ce, &word, &wordlen, &sugg) == FAILURE) {
 		RETURN_THROWS();
 	}
 
@@ -631,7 +631,7 @@ PHP_FUNCTION(enchant_dict_check)
 	size_t wordlen;
 	enchant_dict *pdict;
 
-	if (zend_parse_parameters(ZEND_NUM_ARGS(), "Os", &dict, enchant_dict_ce, &word, &wordlen) == FAILURE) {
+	if (zend_parse_parameters(ZEND_NUM_ARGS(), "Op", &dict, enchant_dict_ce, &word, &wordlen) == FAILURE) {
 		RETURN_THROWS();
 	}
 
@@ -651,7 +651,7 @@ PHP_FUNCTION(enchant_dict_suggest)
 	enchant_dict *pdict;
 	size_t n_sugg;
 
-	if (zend_parse_parameters(ZEND_NUM_ARGS(), "Os", &dict, enchant_dict_ce, &word, &wordlen) == FAILURE) {
+	if (zend_parse_parameters(ZEND_NUM_ARGS(), "Op", &dict, enchant_dict_ce, &word, &wordlen) == FAILURE) {
 		RETURN_THROWS();
 	}
 
@@ -679,7 +679,7 @@ PHP_FUNCTION(enchant_dict_add)
 	size_t wordlen;
 	enchant_dict *pdict;
 
-	if (zend_parse_parameters(ZEND_NUM_ARGS(), "Os", &dict, enchant_dict_ce, &word, &wordlen) == FAILURE) {
+	if (zend_parse_parameters(ZEND_NUM_ARGS(), "Op", &dict, enchant_dict_ce, &word, &wordlen) == FAILURE) {
 		RETURN_THROWS();
 	}
 
@@ -697,7 +697,7 @@ PHP_FUNCTION(enchant_dict_add_to_session)
 	size_t wordlen;
 	enchant_dict *pdict;
 
-	if (zend_parse_parameters(ZEND_NUM_ARGS(), "Os", &dict, enchant_dict_ce, &word, &wordlen) == FAILURE) {
+	if (zend_parse_parameters(ZEND_NUM_ARGS(), "Op", &dict, enchant_dict_ce, &word, &wordlen) == FAILURE) {
 		RETURN_THROWS();
 	}
 
@@ -715,7 +715,7 @@ PHP_FUNCTION(enchant_dict_is_added)
 	size_t wordlen;
 	enchant_dict *pdict;
 
-	if (zend_parse_parameters(ZEND_NUM_ARGS(), "Os", &dict, enchant_dict_ce, &word, &wordlen) == FAILURE) {
+	if (zend_parse_parameters(ZEND_NUM_ARGS(), "Op", &dict, enchant_dict_ce, &word, &wordlen) == FAILURE) {
 		RETURN_THROWS();
 	}
 
@@ -737,7 +737,7 @@ PHP_FUNCTION(enchant_dict_store_replacement)
 
 	enchant_dict *pdict;
 
-	if (zend_parse_parameters(ZEND_NUM_ARGS(), "Oss", &dict, enchant_dict_ce, &mis, &mislen, &cor, &corlen) == FAILURE) {
+	if (zend_parse_parameters(ZEND_NUM_ARGS(), "Opp", &dict, enchant_dict_ce, &mis, &mislen, &cor, &corlen) == FAILURE) {
 		RETURN_THROWS();
 	}
 
diff --git a/ext/enchant/tests/null_bytes.phpt b/ext/enchant/tests/null_bytes.phpt
new file mode 100644
index 00000000000..cdd26cf97d3
--- /dev/null
+++ b/ext/enchant/tests/null_bytes.phpt
@@ -0,0 +1,70 @@
+--TEST--
+null bytes
+--EXTENSIONS--
+enchant
+--SKIPIF--
+<?php
+$broker = enchant_broker_init();
+if (!enchant_broker_list_dicts($broker)) die("skip No broker dicts installed");
+?>
+--FILE--
+<?php
+
+$broker = enchant_broker_init();
+$dicts = enchant_broker_list_dicts($broker);
+$requestDict = enchant_broker_request_dict($broker, $dicts[0]['lang_tag']);
+
+$two_params_broker = [
+    "enchant_broker_request_dict",
+    "enchant_broker_dict_exists",
+];
+
+$two_params_dict = [
+    "enchant_dict_quick_check",
+    "enchant_dict_check",
+    "enchant_dict_suggest",
+    "enchant_dict_add",
+    "enchant_dict_add_to_session",
+    "enchant_dict_is_added",
+];
+
+foreach ($two_params_broker as $func) {
+    try {
+        $func($broker, "foo\0bar");
+    } catch (ValueError $e) {
+        echo $e->getMessage(), "\n";
+    }
+}
+
+foreach ($two_params_dict as $func) {
+    try {
+        $func($requestDict, "foo\0bar");
+    } catch (ValueError $e) {
+        echo $e->getMessage(), "\n";
+    }
+}
+
+try {
+    var_dump(enchant_broker_set_ordering($broker, "foo\0bar", "foo\0bar"));
+} catch (ValueError $e) {
+    echo $e->getMessage(), "\n";
+}
+
+try {
+    var_dump(enchant_dict_store_replacement($requestDict, "foo\0bar", "foo\0bar"));
+} catch (ValueError $e) {
+    echo $e->getMessage(), "\n";
+}
+
+?>
+--EXPECT--
+enchant_broker_request_dict(): Argument #2 ($tag) must not contain any null bytes
+enchant_broker_dict_exists(): Argument #2 ($tag) must not contain any null bytes
+enchant_dict_quick_check(): Argument #2 ($word) must not contain any null bytes
+enchant_dict_check(): Argument #2 ($word) must not contain any null bytes
+enchant_dict_suggest(): Argument #2 ($word) must not contain any null bytes
+enchant_dict_add(): Argument #2 ($word) must not contain any null bytes
+enchant_dict_add_to_session(): Argument #2 ($word) must not contain any null bytes
+enchant_dict_is_added(): Argument #2 ($word) must not contain any null bytes
+enchant_broker_set_ordering(): Argument #2 ($tag) must not contain any null bytes
+enchant_dict_store_replacement(): Argument #2 ($misspelled) must not contain any null bytes