CVE-2026-43866 Apache Camel, Apache Camel: Camel JMS - CVE-2026-40860 fix bypass via DefaultExchangeHolder

What is CVE-2026-43866?

CVE-2026-43866 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, Apache Camel JMS component.

JmsBinding.extractBodyFromJms() in camel-jms - and the equivalent JmsBinding in camel-sjms - deserializes the payload of an incoming JMS ObjectMessage via jakarta.jms.ObjectMessage.getObject() whenever the mapJmsMessage option is enabled (the default) and Camel acts as a JMS consumer. The CVE-2026-40860 hardening added a post-deserialization class check that rejects classes outside the default allow-list java.**;javax.**;org.apache.camel.**;!*. However org.apache.camel.support.DefaultExchangeHolder itself lives in the allow-listed org.apache.camel.** namespace, so an ObjectMessage whose top-level object is a DefaultExchangeHolder passes the check. The receiving side then calls DefaultExchangeHolder.unmarshal() on it without requiring the transferExchange option to be enabled - an asymmetric trust boundary, since the sending side gates ObjectMessage and transferExchange handling but the receiving side did not - writing every non-null field of the holder into the Exchange: the message body, the IN and OUT headers, the exchange properties, the variables, the exchange id and the exception. An attacker who can publish an ObjectMessage to a queue or topic consumed by an affected Camel application can therefore inject arbitrary Exchange state using only universally-trusted java.lang and java.util types, with no deserialization gadget chain required, to manipulate routing and headers, exchange properties and error handling. The same handling applies to camel-sjms and camel-sjms2, and to the JMS-family components built on JmsComponent and JmsBinding: camel-amqp, camel-activemq and camel-activemq6. This is a bypass of the CVE-2026-40860 fix rather than a flaw in it. This issue affects Apache Camel: from 3.0.0 before 4.14.8, from 4.15.0 before 4.18.3, from 4.19.0 before 4.21.0; Apache Camel: from 3.0.0 before 4.14.8, from 4.15.0 before 4.18.3, from 4.19.0 before 4.21.0.

Users are recommended to upgrade to version 4.21.0, 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, JMS ObjectMessage handling is disabled by default in camel-jms, camel-sjms and the JMS-family components (a new objectMessageEnabled option defaults to false at the component and endpoint level), so an incoming ObjectMessage - including a DefaultExchangeHolder payload - is no longer deserialized unless the option is explicitly enabled; only set objectMessageEnabled=true when the consumed JMS destination is fed exclusively by trusted producers. For deployments that cannot upgrade immediately, restrict publish access to the queues and topics consumed by Camel to trusted producers via JMS broker authorization, and do not expose JMS consumers that map ObjectMessage bodies to untrusted networks; a JMS-provider deserialization allow-list does not mitigate this specific bypass because the crafted payload uses only universally-trusted classes.

Weakness: CWE-502

Which versions are affected by CVE-2026-43866?

36 open source packages ship an affected version, including org.apache.camel:camel-activemq, org.apache.camel:camel-activemq6 and org.apache.camel:camel-amqp. It affects 1 product.

Products include Apache Camel.

How do I fix CVE-2026-43866?

Upgrade org.apache.camel:camel-activemq to a fixed version for your release line: 4.14.8, 4.18.3 or 4.21.0.

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

Is CVE-2026-43866 being exploited?

There is no known exploitation of CVE-2026-43866 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-f755-xp6r-8q84, MINI-2p9v-5qwc-8jq8, MINI-38c6-q7j9-pq6p, MINI-p5mc-qxpm-mcpq, MINI-pp77-qqg5-cf8w.