diff --git a/pdf.c b/pdf.c
index 6502f7027039b40e96dff971630dc8de3767e90f..f773872dac9bbdad314abcdcd5bfa745f1ea4e24 100644
--- a/pdf.c
+++ b/pdf.c
@@ -4371,6 +4371,7 @@ process_page_content(struct Env *aux)
 	trailer = H_INDEX(Dict, tok, 1);
 
 	/* fetch Size (a required field) from the trailer dictionary */
+	// XXX validate the presence of this field elsewhere
 	tok = dictentry(trailer, "Size");
 	if (tok == NULL || tok->token_type != TT_SINT) {
 		log_message(5, "VIOLATION[5]: error parsing trailer section!"