diff --git a/src/quic_tp.c b/src/quic_tp.c
index f7f8d7d..f83ed86 100644
--- a/src/quic_tp.c
+++ b/src/quic_tp.c
@@ -191,6 +191,7 @@
 		/* TODO: not supported */
 		return 0;
 
+	tp->nb_others = (end - (const unsigned char *)tp->others) / sizeof *tp->others;
 	for (ver = tp->others; ver < (const uint32_t *)end; ver++) {
 		if (!tp->negotiated_version) {
 			int i;