CVE-2026-43865

CVE-2026-43865 is a high-severity vulnerability in Apache Camel with a CVSS 3.x base score of 8.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-502.

Key facts

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.

Frequently asked questions

What is CVE-2026-43865?
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.
How severe is CVE-2026-43865?
CVE-2026-43865 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-43865 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (52nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-43865?
CVE-2026-43865 affects Apache Camel. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-43865?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2026-43865 published?
CVE-2026-43865 was published on 2026-07-06 and last updated on 2026-07-07.

References

Affected products (1)

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