diff --git a/src/persist_read_v5.c b/src/persist_read_v5.c
index 480a383a..d1a4b1e9 100644
--- a/src/persist_read_v5.c
+++ b/src/persist_read_v5.c
@@ -172,6 +172,7 @@ int persist__chunk_base_msg_read_v56(FILE *db_fptr, struct P_base_msg *chunk, ui
 	chunk->F.source_port = ntohs(chunk->F.source_port);
 
 	length -= (uint32_t)(sizeof(struct PF_base_msg) + chunk->F.payloadlen + chunk->F.source_id_len + chunk->F.source_username_len + chunk->F.topic_len);
+	if(length > MQTT_MAX_PAYLOAD) goto error;
 
 	if(chunk->F.source_id_len){
 		rc = persist__read_string_len(db_fptr, &chunk->source.id, chunk->F.source_id_len);