CVE-2020-27222: Eclipse Californium

High severity, CVSS 7.5. EPSS: 0.9% chance of exploitation in the next 30 days.

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.

Affected products

• Eclipse Californium: from 2.3.0, up to and including 2.6.0

Published 2021-02-03. Last modified 2026-06-17.