Severity:
CVSS 4.0: 10.0 (critical)
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
Affected versions:
- Apache Camel (org.apache.camel:camel-hazelcast) 4.0.0 before 4.18.5
- Apache Camel (org.apache.camel:camel-hazelcast) 4.19.0 before 4.22.1
- Apache Camel (org.apache.camel:camel-hazelcast) 4.18.5 unaffected
- Apache Camel (org.apache.camel:camel-hazelcast) 4.22.1 unaffected
- Apache Camel (org.apache.camel:camel-hazelcast) 4.23.0 unaffected
Description:
Deserialization of Untrusted Data vulnerability in Apache Camel.
This issue affects Apache Camel: from 4.0.0 before 4.18.5, from 4.19.0 before
4.22.1.
The camel-hazelcast component applies a default Hazelcast
JavaSerializationFilterConfig to the instances it creates from its own
configuration, a protection introduced by CVE-2026-43865. That change did not
reach two of the configuration paths Camel builds itself, so those paths
continued to create Hazelcast instances whose Java deserialization is
unrestricted. ReplicatedHazelcastAggregationRepository extends
HazelcastAggregationRepository but overrides doStart() without calling
super.doStart(), keeping its own copy of the bootstrap block, and therefore
never received the filter: a route using it without supplying a
hazelcastInstance starts a Hazelcast member that deserializes values read from
the backing ReplicatedMap with no class restriction.
HazelcastDefaultComponent#getOrCreateHzClientInstance() builds its own
ClientConfig when hazelcastMode=client is selected and neither a referenced
ClientConfig nor hazelcastConfigUri is supplied, and likewise applied no
filter, so client-mode endpoints behaved differently from node-mode endpoints
for an otherwise identical configuration. In both cases an attacker able to
publish into the Hazelcast cluster that the affected instance is attached to
can cause a serialized Java object of their choosing to be deserialized inside
Hazelcast's own serialization layer, before Camel processes the exchange,
resulting in remote code execution. Hazelcast clusters have neither
authentication nor TLS enabled by default. Selecting client mode is a topology
choice rather than a security option, so neither path required the deployment
to opt in to unsafe behaviour.
Users are recommended to upgrade to version 4.23.0, which fixes the issue. If
users are on the 4.22.x releases stream, then they are suggested to upgrade to
4.22.1. If users are on the 4.18.x releases stream, then they are suggested to
upgrade to 4.18.5. The 4.14.x releases stream and earlier reached end of life
before this issue was resolved and will not receive a fix, so deployments on
those lines must move to a supported release. For deployments that cannot
upgrade immediately, supply an explicit Hazelcast configuration carrying a
JavaSerializationFilterConfig, or inject a pre-built HazelcastInstance, since a
user-supplied configuration is never overwritten by Camel. Alternatively set
the JVM-wide filter
-Djdk.serialFilter=!java.net.;java.;javax.;org.apache.camel.;!* and enable
Hazelcast cluster authentication and TLS to restrict who can reach the cluster.
Solution:
Upgrade to Apache Camel 4.23.0, which fixes the issue. Users on the 4.22.x
releases stream should upgrade to 4.22.1. Users on the 4.18.x releases stream
should upgrade to 4.18.5. The 4.14.x releases stream and earlier reached end of
life before this issue was resolved and will not receive a fix, so deployments
on those lines must move to a supported release. The fix adds an
applyDefault(ClientConfig) overload to HazelcastSerializationFilterHelper and
calls the helper on both previously uncovered paths, so every Hazelcast
configuration that Camel builds itself now carries the default filter, which
whitelists the class name prefixes java., javax. and org.apache.camel. and
blacklists java.net. A user-supplied Config, ClientConfig or HazelcastInstance
is still left untouched.
Work Arounds:
Supply an explicit Hazelcast configuration carrying a
JavaSerializationFilterConfig, or inject a pre-built HazelcastInstance, since a
user-supplied configuration is never overwritten by Camel. Alternatively set
the JVM-wide filter
-Djdk.serialFilter=!java.net.;java.;javax.;org.apache.camel.;!* and enable
Hazelcast cluster authentication and TLS to restrict who can reach the cluster.
Credit:
cattier from TCBS (finder)
Leon Zlobecki (finder)
Andrea Cosentino (remediation developer)
References:
https://camel.apache.org/security/CVE-2026-78162.html
https://issues.apache.org/jira/browse/CAMEL-24413
https://issues.apache.org/jira/browse/CAMEL-24420
https://github.com/apache/camel/pull/25566
https://github.com/apache/camel/pull/25595
https://github.com/apache/camel/pull/25599
https://github.com/apache/camel/pull/25600
https://camel.apache.org/security/CVE-2026-43865.html
https://camel.apache.org/
https://www.cve.org/CVERecord?id=CVE-2026-78162
