CVE-2026-43865 Apache Camel-Hazelcast: Unsafe Java deserialization in default-configured managed Hazelcast instances enables remote code execution

What is CVE-2026-43865?

CVE-2026-43865 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 Hazelcast component.

The camel-hazelcast component creates and manages Hazelcast instances using a default configuration that applies no Java deserialization filter. When Camel builds the Hazelcast Config itself - that is, when no user-supplied HazelcastInstance, hazelcastConfigUri, or referenced Config bean is provided - neither Hazelcast's JavaSerializationFilterConfig nor a Camel-side ObjectInputFilter is configured, so objects received over the Hazelcast cluster protocol are deserialized inside Hazelcast's own serialization layer (ObjectInputStream.readObject) before Camel ever processes them. An attacker who can join or otherwise reach the Hazelcast cluster can publish a crafted serialized Java object that is then deserialized on every Camel node, resulting in remote code execution. The exposure is present by default and requires no opt-in endpoint configuration: any route using a hazelcast consumer (hazelcast-topic, hazelcast-queue, hazelcast-seda, hazelcast-map, hazelcast-multimap, hazelcast-replicatedmap, hazelcast-list, hazelcast-set), as well as the HazelcastAggregationRepository and HazelcastIdempotentRepository, is affected whenever the managed instance is created from Camel's default configuration. 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 4.21.0.

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. The fix makes Camel apply a default Hazelcast JavaSerializationFilterConfig (whitelisting the java., javax. and org.apache.camel. class-name prefixes and blacklisting java.net.) to instances it creates from its own default configuration, while leaving any user-supplied Config or HazelcastInstance untouched. For deployments that cannot upgrade immediately, configure a deserialization filter on the Hazelcast instance (Hazelcast JavaSerializationFilterConfig, or the JVM-wide system property -Djdk.serialFilter=!java.net.**;java.**;javax.**;org.apache.camel.**;!*) and enable Hazelcast cluster authentication and TLS to restrict who can reach the cluster.

Weakness: CWE-502

Which versions are affected by CVE-2026-43865?

6 open source packages ship an affected version, including org.apache.camel:camel-hazelcast. It affects 1 product.

Products include Apache Camel.

How do I fix CVE-2026-43865?

Upgrade org.apache.camel:camel-hazelcast 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-2026-43865 being exploited?

There is no known exploitation of CVE-2026-43865 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-xww8-mxqw-m84w.