An attacker can arbitrarily craft malicious DDS Participants (or ROS 2 Nodes) with valid certificates to compromise and get full control of the attacked secure DDS databus system by exploiting vulnerable attributes in the configuration of PKCS#7 certificate’s validation. This is caused by a non-compliant implementation of permission document verification used by some DDS vendors. Specifically, an improper use of the OpenSSL PKCS7_verify function used to validate S/MIME signatures.