Apache Camel: Camel-Dynamic-Router Control Endpoint Compiles Predicate Expressions Supplied by Control Messages

Improper Control of Generation of Code ('Code Injection'), Improper Neutralization of Special Elements used in an Expression Language Statement ('Expression Language Injection') vulnerability in Apache Camel. This issue affects Apache Camel: from 4.4.0 before 4.18.5, from 4.19.0 before 4.22.1. The dynamic-router-control endpoint, introduced in 4.4.0, lets routing participants manage Dynamic Router subscriptions by sending control messages. When it handled a subscribe or update request, DynamicRouterControlProducer took the subscription predicate and the name of the language used to compile it from the incoming message, either from the predicate and expressionLanguage fields of a DynamicRouterControlMessage body or from the CamelDynamicRouterPredicate and CamelDynamicRouterExpressionLanguage headers. DynamicRouterControlService then resolved that language from the CamelContext and compiled the expression into a Predicate, with no allow-list and no opt-in. The compiled predicate was added to the channel's rule base and evaluated against every exchange routed through the corresponding dynamic-router endpoint for as long as the subscription existed. A route that forwards messages from an external transport to the control endpoint, as shown in the component documentation for routing participants in other JVMs or applications, therefore let any actor able to send a message on that transport supply an expression of their choosing, which was evaluated with the privileges of the Camel