diff --git a/include/net/ndisc.h b/include/net/ndisc.h
index 7d107113f988a6a169b06ee2622d89bdacf2580a..9205a76d967a03e4162bad03f2f4e53d6e976506 100644
--- a/include/net/ndisc.h
+++ b/include/net/ndisc.h
@@ -41,7 +41,7 @@ enum {
 	ND_OPT_DNSSL = 31,		/* RFC6106 */
 	ND_OPT_6CO = 34,		/* RFC6775 */
 	ND_OPT_CAPTIVE_PORTAL = 37,	/* RFC7710 */
-	ND_OPT_PREF64 = 38,		/* RFC-ietf-6man-ra-pref64-09 */
+	ND_OPT_PREF64 = 38,		/* RFC8781 */
 	__ND_OPT_MAX
 };