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CVE-2026-66909

Apache Cxf remote code execution

9.8 CRITICALEPSS 1.15%
  1. Published6 Aug 2026

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.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

Apache Cxf≥ 4.0.0 < 4.1.8 · ≥ 4.2.0 < 4.2.3 · < 3.6.12

Remediation

Fixed in
Apache Cxf≥ 4.1.8

References

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Frequently asked

Is CVE-2026-66909 being actively exploited?

CVE-2026-66909 is not in the CISA KEV catalog. Its EPSS exploit probability is 1.15%.

How severe is CVE-2026-66909?

CVE-2026-66909 has a CVSS 3.1 base score of 9.8, rated critical. EPSS estimates a 1.15% probability of exploitation.

Which products are affected by CVE-2026-66909?

Affected products include Apache Cxf.

How do I fix CVE-2026-66909?

Upgrade affected software to a fixed version, for example Apache Cxf 4.1.8 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-66909 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.