diff --git a/plugins/epan/opcua/opcua.c b/plugins/epan/opcua/opcua.c
index 2eb3884f5b..e1dd43607a 100644
--- a/plugins/epan/opcua/opcua.c
+++ b/plugins/epan/opcua/opcua.c
@@ -283,7 +283,14 @@ static int dissect_opcua_message(tvbuff_t *tvb, packet_info *pinfo, proto_tree *
                        this way Wireshark reassembles the message, as it expects the fragment
                        sequence numbers to start at 0 */
                     for (frag_i = frag_msg->next; frag_i; frag_i = frag_i->next) {}
-                    opcua_seqnum = frag_i->offset + 1;
+                    if (frag_i) {
+                        opcua_seqnum = frag_i->offset + 1;
+                    } else {
+                        /* We should never have a fragment head with no fragment items, but
+                         * just in case.
+                         */
+                        opcua_seqnum = 0;
+                    }
 
                     if (chunkType == 'F')
                     {