Californium Failing DTLS handshakes causes Data Loss due to throttling blocking processing of records

Eclipse Californium is a Java implementation of RFC7252 - Constrained Application Protocol for IoT Cloud services. In versions prior to 3.7.0, and 2.7.4, Californium is vulnerable to a Denial of Service. Failing handshakes don't cleanup counters for throttling, causing the threshold to be reached without being released again. This results in permanently dropping records. The issue was reported for certificate based handshakes, but may also affect PSK based handshakes. It generally affects client and server as well. This issue is patched in version 3.7.0 and 2.7.4. There are no known workarounds. main: commit 726bac57659410da463dcf404b3e79a7312ac0b9 2.7.x: commit 5648a0c27c2c2667c98419254557a14bac2b1f3f