In Eclipse Californium version 2.3.0 to 2.6.0, the certificate based (x509 and RPK) DTLS handshakes accidentally fails, because the DTLS server side s...

In Eclipse Californium version 2.3.0 to 2.6.0, the certificate based (x509 and RPK) DTLS handshakes accidentally fails, because the DTLS server side sticks to a wrong internal state. That wrong internal state is set by a previous certificate based DTLS handshake failure with TLS parameter mismatch. The DTLS server side must be restarted to recover this. This allow clients to force a DoS.