diff --git a/ldpd/labelmapping.c b/ldpd/labelmapping.c
index 5e1b422a41..a656626356 100644
--- a/ldpd/labelmapping.c
+++ b/ldpd/labelmapping.c
@@ -723,6 +723,14 @@ tlv_decode_fec_elm(struct nbr *nbr, struct ldp_msg *msg, char *buf,
 		/* Prefix Length */
 		map->fec.prefix.prefixlen = buf[off];
 		off += sizeof(uint8_t);
+		if ((map->fec.prefix.af == AF_IPV4
+		     && map->fec.prefix.prefixlen > IPV4_MAX_PREFIXLEN)
+		    || (map->fec.prefix.af == AF_IPV6
+			&& map->fec.prefix.prefixlen > IPV6_MAX_PREFIXLEN)) {
+			session_shutdown(nbr, S_BAD_TLV_VAL, msg->id,
+			    msg->type);
+			return (-1);
+		}
 		if (len < off + PREFIX_SIZE(map->fec.prefix.prefixlen)) {
 			session_shutdown(nbr, S_BAD_TLV_LEN, msg->id,
 			    msg->type);