Server-Side Request Forgery (SSRF) vulnerability in Apache Camel AS2 component.

This issue affects Apache Camel: from 4.0.0 before 4.18.5, from 4.19.0 before 4.22.1.

In the AS2 protocol the sender of a message may request that the Message Disposition Notification be returned asynchronously to an address the sender supplies. camel-as2 took that address from the inbound message and used it as the destination for the outgoing receipt without constraining it to anything the deployment had configured. A remote partner therefore chose the host the Camel instance would connect to when delivering the MDN. That gives server-side request forgery from the position of the AS2 receiver, including reaching hosts that are only routable from inside the deployment's network, and where the outbound connection carries credentials configured for MDN delivery those credentials are presented to the attacker-chosen destination.

Upgrade to Apache Camel 4.23.0, which fixes the issue. Users on the 4.18.x LTS releases stream should upgrade to 4.18.5. Users on the 4.22.x LTS releases stream should upgrade to 4.22.1. The asynchronous MDN destination is now constrained rather than taken verbatim from the inbound message. For deployments that cannot upgrade immediately, restrict outbound connectivity from the AS2 receiver to the partner endpoints it legitimately delivers receipts to, and do not attach credentials to MDN delivery that are valid for any host other than those partners.