CVE-2026-66909: Apache CXF: Unsafe deserialization of inbound JMS ObjectMessage

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-08-06 · updated 2026-10-24
Weakness: CWE-502

Description

Apache CXF's JMS transport deserializes the body of any inbound JMS ObjectMessage using native Java deserialization, with no type restrictions in place. Any attacker able to place a message on the service's JMS destination can submit a malicious serialized object, leading to denial of service or, if a suitable gadget class is on the classpath, remote code execution. The fix disables ObjectMessage deserialization by default, with a configuration switch to re-enable it if needed. Users are recommended to upgrade to versions 4.2.3 or 4.1.8 or 3.6.12, which fix this issue.

Affected products

Apache Software Foundation Apache CXF: before 3.6.12; from 4.0.0 before 4.1.8; from 4.2.0 before 4.2.3 — fixed in 3.6.12, 4.1.8, 4.2.3

How to fix

Upgrade to a fixed version: Apache Software Foundation Apache CXF 3.6.12, 4.1.8, 4.2.3. Check the vendor advisory for mitigations.

References

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