Medium [CVE-2026-59230] Improper input validation vulnerability in Apache Camel

Improper input validation vulnerability in Apache Camel.

This issue affects Apache Camel: from 2.17.0 before 4.14.9, from 4.15.0 before 4.18.4, from 4.19.0 before 4.22.0.

The camel-mail component ships a MimeMultipart data format that can unmarshal a MIME multipart message.

When it is configured with headersInline set to true, the unmarshal path copies the MIME headers of the incoming message onto the Camel message: it enumerates every header that is not one of the three standard ones it generates itself - Message-ID, MIME-Version and Content-Type - and calls setHeader for each, applying no HeaderFilterStrategy.

The names of those MIME headers come from the message being unmarshalled, so a sender able to influence the message could place a header whose name falls in the Camel-internal namespace and have it set on the Exchange.

Camel components read control headers from that namespace to override their configured behaviour - the camel-sql producer, for instance, takes the statement to execute from a Camel header when one is present - so an injected header could redirect what a downstream step in the route does with data the route author never intended it to take from the message.

Which sinks are reachable, and what the consequences are, depends entirely on what the route does after the unmarshal step.