Summary
Apache Camel-Vertx-Http and Camel-Netty-Http: Unsafe Java deserialization of HTTP response bodies via a raw ObjectInputStream when transferException is enabled
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.
Impact
Untrusted serialized data is processed by a deserializer that can instantiate arbitrary objects or execute code as a side effect. Typical impact: arbitrary code execution or logic abuse.
CVE-2026-40859 has a CVSS score of 8.1 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (4.14.8, 4.18.3, 4.20.0); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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org.apache.camel:camel-vertx-http to 4.14.8 or later; org.apache.camel:camel-vertx-http to 4.18.3 or later; org.apache.camel:camel-vertx-http to 4.20.0 or later; org.apache.camel:camel-netty-http to 4.14.8 or later; org.apache.camel:camel-netty-http to 4.18.3 or later; org.apache.camel:camel-netty-http to 4.20.0 or later
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2026-40859? CVE-2026-40859 is a high-severity insecure deserialization vulnerability in org.apache.camel:camel-vertx-http (maven), affecting versions >= 4.0.0, < 4.14.8. It is fixed in 4.14.8, 4.18.3, 4.20.0. Untrusted serialized data is processed by a deserializer that can instantiate arbitrary objects or execute code as a side effect.
- How severe is CVE-2026-40859? CVE-2026-40859 has a CVSS score of 8.1 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which packages are affected by CVE-2026-40859?
org.apache.camel:camel-vertx-http(maven) (versions >= 4.0.0, < 4.14.8)org.apache.camel:camel-netty-http(maven) (versions >= 4.0.0, < 4.14.8)
- Is there a fix for CVE-2026-40859? Yes. CVE-2026-40859 is fixed in 4.14.8, 4.18.3, 4.20.0. Upgrade to this version or later.
- Is CVE-2026-40859 exploitable, and should I be worried? Whether CVE-2026-40859 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-40859 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-40859?
- Upgrade
org.apache.camel:camel-vertx-httpto 4.14.8 or later - Upgrade
org.apache.camel:camel-vertx-httpto 4.18.3 or later - Upgrade
org.apache.camel:camel-vertx-httpto 4.20.0 or later - Upgrade
org.apache.camel:camel-netty-httpto 4.14.8 or later - Upgrade
org.apache.camel:camel-netty-httpto 4.18.3 or later - Upgrade
org.apache.camel:camel-netty-httpto 4.20.0 or later
- Upgrade