diff --git a/contrib/tcpdump/print-pfsync.c b/contrib/tcpdump/print-pfsync.c
--- a/contrib/tcpdump/print-pfsync.c
+++ b/contrib/tcpdump/print-pfsync.c
@@ -86,7 +86,7 @@
 {
 	struct pfsync_header *hdr = (struct pfsync_header *)bp;
 
-	if (len < PFSYNC_HDRLEN)
+	if (len < PFSYNC_HDRLEN || !ND_TTEST_LEN(bp, len))
 		ND_PRINT("[|pfsync]");
 	else
 		pfsync_print(ndo, hdr, bp + sizeof(struct pfsync_header),