diff --git a/ext/sockets/sockets.c b/ext/sockets/sockets.c
index 86b7f046945..0e11280c914 100644
--- a/ext/sockets/sockets.c
+++ b/ext/sockets/sockets.c
@@ -1717,7 +1717,7 @@ PHP_FUNCTION(socket_sendto)
 		case AF_UNIX:
 			memset(&s_un, 0, sizeof(s_un));
 
-			if (addr_len >= sizeof(s_un.sun_path)) {
+			if (ZSTR_LEN(addr) >= sizeof(s_un.sun_path)) {
 				zend_argument_value_error(5, "must be less than %d", sizeof(s_un.sun_path));
 				RETURN_THROWS();
 			}