CVE-2026-40859 Apache Camel-Vertx-Http and Camel-Netty-Http: Unsafe Java deserialization of HTTP response bodies via a raw ObjectInputStream when transferException is enabled

What is CVE-2026-40859?

CVE-2026-40859 is a high-severity unsafe deserialization vulnerability in Apache Camel, published on 6 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Deserialization of Untrusted Data vulnerability in Apache Camel.

The camel-vertx-http component deserializes HTTP response bodies carrying the Content-Type application/x-java-serialized-object using a raw java.io.ObjectInputStream, without applying any ObjectInputFilter (VertxHttpHelper.deserializeJavaObjectFromStream) This deserialization path is reached only when the producer endpoint is configured with transferException=true (or the component-level allowJavaSerializedObject=true) and throwExceptionOnFailure is left at its default value of true; in that case a backend HTTP response with a 5xx status and the application/x-java-serialized-object content type has its body deserialized with no class restrictions. An attacker who controls the backend the Camel producer talks to - through a man-in-the-middle position on an unencrypted (plain HTTP) connection, or by compromising the backend service - can return a crafted serialized Java object and, if a suitable gadget chain is present on the classpath, achieve remote code execution on the Camel application host. The path is not reachable in the default configuration, where transferException is false. This issue affects Apache Camel: from 4.0.0 before 4.14.8, from 4.15.0 before 4.18.3, from 4.19.0 before 4.20.0.

Users are recommended to upgrade to version 4.20.0, which fixes the issue. If users are on the 4.14.x LTS releases stream, then they are suggested to upgrade to 4.14.8. If users are on the 4.18.x releases stream, then they are suggested to upgrade to 4.18.3. After upgrading, the deserialization performed by both helper utilities is constrained by a default ObjectInputFilter (allow-list java.**;javax.**;org.apache.camel.**;!*), which can be customised through the new deserializationFilter endpoint option or the JVM-wide -Djdk.serialFilter system property. For deployments that cannot upgrade immediately: do not enable transferException=true (or allowJavaSerializedObject=true) on producers that talk to untrusted or network-reachable backends; ensure producer connections use TLS (https) so that a response cannot be substituted by a man-in-the-middle; and, where the option is required, set an explicit -Djdk.serialFilter allow-list (for example java.**;org.apache.camel.**;!*) to constrain deserialization.

Weakness: CWE-502

Which versions are affected by CVE-2026-40859?

12 open source packages ship an affected version, including org.apache.camel:camel-netty-http and org.apache.camel:camel-vertx-http. It affects 1 product.

Products include Apache Camel.

How do I fix CVE-2026-40859?

Upgrade org.apache.camel:camel-netty-http to a fixed version for your release line: 4.14.8, 4.18.3 or 4.20.0.

Upgrade, and only deserialise data from trusted sources or with an allow-list of types. More about Unsafe deserialization.

Is CVE-2026-40859 being exploited?

There is no known exploitation of CVE-2026-40859 in the wild and no public exploit code.

Public exploit code: 1 proofs of concept on GitHub.

Other vulnerabilities in Apache Camel

• CVE-2026-33453 Apache camel-coap allows header injection that can lead to remote code execution Critical 10.0
• CVE-2026-40453 Apache Camel has an incomplete fix for CVE-2025-27636 Critical 9.9
• CVE-2026-80351 Apache Camel K: Camel K Tenant repositories reach Maven execution inside operator pod Critical 9.8
• CVE-2026-80352 Apache Camel K: Camel K Master trait serviceAccountName YAML injection lets CR author apply arbitrary objects Critical 9.8
• CVE-2026-71300 Apache Camel: Camel-Atmosphere-Websocket: WebSocket dispatch header injection Critical 9.8

All Apache Camel vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-6qw3-4796-5984.