Suricata is a network Intrusion Detection System, Intrusion Prevention System and Network Security Monitoring engine. Crafted modbus traffic can lead to unlimited resource accumulation within a flow. Upgrade to 7.0.6. Set a limited stream.reassembly.depth to reduce the issue.
https://redmine.openinfosecfoundation.org/issues/6988
https://redmine.openinfosecfoundation.org/issues/6987
https://github.com/OISF/suricata/security/advisories/GHSA-59qg-h357-69fq
https://github.com/OISF/suricata/commit/a753cdbe84caee3b66d0bf49b2712d29a50d67ae