Attack Chain

1. Attacker identifies an internet-facing Apache Camel application that routes HTTP requests to a Kafka producer, specifically utilizing the camel-kafka component.
2. Attacker crafts an HTTP POST request targeting the application's vulnerable endpoint (e.g., /feedback).
3. The request includes a specially crafted HTTP header, kafka.OVERRIDE_TOPIC, with a value corresponding to a sensitive Kafka topic (e.g., account-commands).
4. The Apache Camel application, due to improper input validation in the KafkaProducer.evaluateTopic() method, processes the kafka.OVERRIDE_TOPIC header without proper filtering by HttpHeaderFilterStrategy.
5. Instead of sending the message to the application's pre-configured Kafka topic (e.g., user-feedback), the camel-kafka component redirects the message to the attacker-specified topic.
6. The forged message, containing attacker-chosen content (e.g., {"action":"GRANT_ADMIN","account":"attacker@evil.example"}), is injected into the sensitive Kafka topic.
7. A downstream service, consuming from the now-compromised Kafka topic, processes the malicious message, potentially leading to unauthorized actions or data manipulation.

Impact

This vulnerability, CVE-2026-49098, enables unauthenticated attackers to perform cross-topic message injection, leading to severe data integrity compromise. By injecting forged commands or messages into privileged Kafka topics, attackers can potentially trigger unauthorized actions, manipulate critical business logic, or introduce malicious data that could be consumed by downstream services. The observed impact includes the injection of commands like GRANT_ADMIN into an account-commands topic, directly enabling privilege escalation or other unauthorized administrative actions. Organizations using affected Apache Camel versions in environments bridging HTTP consumers to Kafka producers face a high risk of integrity violations if not patched.

Recommendation

• Patch CVE-2026-49098 immediately by upgrading Apache Camel to version 4.14.8, 4.18.3, or 4.21.0 to address the improper input validation.
• As an interim mitigation until upgrading, configure your Apache Camel routes to explicitly strip all kafka.* headers from untrusted ingress points before they reach the kafka: producer using a removeHeaders("kafka.*") policy.
• Review any existing Apache Camel routes that intentionally set Kafka topic, timestamp, or partition via headers; after upgrading, these routes must be updated to use the new CamelKafka* header naming convention as outlined in the Apache Camel 4.x upgrade guide.