CVE-2026-71300 — camel-atmosphere-websocket dispatch header injection

Runnable proof-of-concept reproducer for the Apache Camel vulnerability where the camel-atmosphere-websocket producer selects its WebSocket recipients from websocket.* Exchange headers whose names fall outside the Camel namespace — so an HTTP HeaderFilterStrategy (which strips only Camel* / camel*) admits them, and an external sender can take over the producer's dispatch decision.

Camel Quarkus: there is no camel-quarkus-atmosphere-websocket extension, so this component cannot be run on Camel Quarkus — the reproducer is Spring Boot only.

What it demonstrates

A route bridges an HTTP consumer into an atmosphere-websocket producer, delivering each HTTP message to a single pinned WebSocket recipient (the "victim") by setting the websocket.connectionKey header itself. But WebsocketProducer.process tests the list header websocket.connectionKey.list before the single-key header, and that dotted name is not in the Camel namespace, so the HTTP header filter does not strip it. An injected websocket.connectionKey.list header therefore passes from the request into the Exchange and overrides the pinned recipient — the message meant for the victim is delivered to an attacker-chosen connection instead.

POST /notify ──► setHeader(websocket.connectionKey = victim) ──► atmosphere-websocket producer ──► victim peer
   │                                                                        ▲
   └─ injected header  websocket.connectionKey.list: <attacker key>  ───────┘  (tested first → wins)

On the test harness. The atmosphere WebSocket runtime needs the servlet container's WebSocket upgrade and the framework's own initialization, which cannot be driven from a plain standalone Spring Boot app. This reproducer therefore exercises the real WebsocketProducer dispatch logic over a real HTTP ingress — only the two connected peers are stand-ins registered directly into the endpoint's WebSocketStore (as the atmosphere framework would register real browser connections). The header-filter bypass and the producer's dispatch precedence — the actual vulnerability — are exercised for real.

cd camel-spring-boot
mvn clean package
docker compose up -d --build
curl -s http://localhost:8080/exploit/attack
docker compose down

Expected output on an affected build:

1) Benign POST /notify (no injected header):
     victim received:   [hello for the victim]
     attacker received: []
2) Injected POST /notify with header 'websocket.connectionKey.list: attacker-connection-key':
     victim received:   []
     attacker received: [private data meant for the victim, ...]
>>> PROVEN: ... delivering a message meant for the victim to an attacker-chosen WebSocket connection instead: true

Vulnerability Summary

Advisory: https://camel.apache.org/security/CVE-2026-71300.html

The fix

The dispatch header constants were renamed into the Camel namespace — CamelAtmosphereWebsocketConnectionKey, CamelAtmosphereWebsocketConnectionKeyList, CamelAtmosphereWebsocketSendToAll — so the HTTP HeaderFilterStrategy strips them at the transport boundary and an external sender can no longer inject them. The related camel-undertow websocket path is covered by CVE-2026-78329.

Disclaimer

This repository is published for educational and defensive purposes: to help Apache Camel users understand the vulnerability, verify whether they are affected, and confirm that upgrading resolves it. Do not use this material against systems you do not own or operate.