diff --git a/ext/standard/url_scanner_ex.re b/ext/standard/url_scanner_ex.re
index a4a48b6bf60ee..77b4d79793b65 100644
--- a/ext/standard/url_scanner_ex.re
+++ b/ext/standard/url_scanner_ex.re
@@ -140,6 +140,7 @@ static int php_ini_on_update_hosts(zend_ini_entry *entry, zend_string *new_value
 		if (keylen > 0) {
 			/* Note: the hash table is persistently allocated, so the strings must be too! */
 			tmp_key = zend_string_init(key, keylen, true);
+			GC_MAKE_PERSISTENT_LOCAL(tmp_key);
 			zend_hash_add_empty_element(hosts, tmp_key);
 			zend_string_release_ex(tmp_key, true);
 		}