Suricata is a network Intrusion Detection System, Intrusion Prevention System and Network Security Monitoring engine. Prior to versions 7.0.16 and 8.0.5, a crafted rule using mixed-case frame syntax could trigger a heap buffer overflow while Suricata is loading signatures. The issue is reached during rule parsing/loading rather than by network traffic alone. Versions 7.0.16 and 8.0.5 contain a fix. As a workaround, preprocess rules to check that frames are all lowercase and/or only load trusted rulesets.