diff --git a/ext/dom/characterdata.c b/ext/dom/characterdata.c
index 2ff65a314d3..0a0373a5c1d 100644
--- a/ext/dom/characterdata.c
+++ b/ext/dom/characterdata.c
@@ -70,7 +70,7 @@ int dom_characterdata_data_write(dom_object *obj, zval *newval)
 		return FAILURE;
 	}
 
-	xmlNodeSetContentLen(nodep, (xmlChar *) ZSTR_VAL(str), ZSTR_LEN(str) + 1);
+	xmlNodeSetContentLen(nodep, (xmlChar *) ZSTR_VAL(str), ZSTR_LEN(str));
 
 	zend_string_release_ex(str, 0);
 	return SUCCESS;
diff --git a/ext/dom/node.c b/ext/dom/node.c
index 0fa4d66cbc0..1caaad0ed36 100644
--- a/ext/dom/node.c
+++ b/ext/dom/node.c
@@ -185,7 +185,7 @@ int dom_node_node_value_write(dom_object *obj, zval *newval)
 		case XML_COMMENT_NODE:
 		case XML_CDATA_SECTION_NODE:
 		case XML_PI_NODE:
-			xmlNodeSetContentLen(nodep, (xmlChar *) ZSTR_VAL(str), ZSTR_LEN(str) + 1);
+			xmlNodeSetContentLen(nodep, (xmlChar *) ZSTR_VAL(str), ZSTR_LEN(str));
 			break;
 		default:
 			break;
diff --git a/ext/dom/processinginstruction.c b/ext/dom/processinginstruction.c
index c40d24d18ce..1f85f91b281 100644
--- a/ext/dom/processinginstruction.c
+++ b/ext/dom/processinginstruction.c
@@ -130,7 +130,7 @@ int dom_processinginstruction_data_write(dom_object *obj, zval *newval)
 
 	php_libxml_invalidate_node_list_cache_from_doc(nodep->doc);
 
-	xmlNodeSetContentLen(nodep, (xmlChar *) ZSTR_VAL(str), ZSTR_LEN(str) + 1);
+	xmlNodeSetContentLen(nodep, (xmlChar *) ZSTR_VAL(str), ZSTR_LEN(str));
 
 	zend_string_release_ex(str, 0);
 	return SUCCESS;