A message body that is deeply nested and decoded by pn_message_body() could overflow the stack and cause a crash. This issue affects Apache Qpid Proton C: through 0.40.0. Users are recommended to upgrade to version 0.41.1, which fixes the issue.
https://lists.apache.org/thread.html/7v54gx7o1ptxcz3h9549w3h9oxo3ns28