From Fuse 7.9, camel-undertow supports "handlers" option for the consumer endpoint.

camel-2.23.2.fuse-790054-redhat-00001/components/camel-undertow/src/test/resources/HandlersSpringTest.xml
camel-2.23.2.fuse-790054-redhat-00001/components/camel-undertow/src/test/java/org/apache/camel/component/undertow/UndertowHandlersSpringTest.java

However, the official document for Fuse 7.10 still does not have an description for the camel-undertow consumer endpoint option, "handlers".
https://access.redhat.com/documentation/en-us/red_hat_fuse/7.10/html/apache_camel_component_reference/undertow-component

Community document has an explanation for it.
https://camel.apache.org/components/3.15.x/undertow-component.html