CVE-2026-44417: Apache CXF RCE Vulnerability

CVE-2026-44417 Overview

CVE-2026-44417 is a remote code execution vulnerability in Apache CXF caused by an incomplete fix for CVE-2025-48913. The original patch did not cover all code paths that process untrusted Java Message Service (JMS) configuration. Attackers with permission to configure JMS for Apache CXF can reach a secondary path that leads to code execution. The flaw is tracked under CWE-20: Improper Input Validation. Apache has released fixed versions 4.2.1, 4.1.6, and 3.6.11.

Critical Impact

Untrusted users who can configure JMS in Apache CXF can execute arbitrary code on the host, fully compromising confidentiality, integrity, and availability of the affected service.

Affected Products

• Apache CXF versions prior to 3.6.11
• Apache CXF versions prior to 4.1.6
• Apache CXF 4.2.0 (fixed in 4.2.1)

Discovery Timeline

• 2026-05-22 - CVE-2026-44417 published to NVD
• 2026-05-22 - Last updated in NVD database

Technical Details for CVE-2026-44417

Vulnerability Analysis

Apache CXF is an open source services framework used to build SOAP and REST web services in Java. The framework supports JMS as a transport, and JMS endpoints are configurable through application-supplied parameters. CVE-2025-48913 previously addressed an issue where untrusted JMS configuration could be abused to reach a JNDI lookup that loaded attacker-controlled objects, resulting in remote code execution.

The fix for CVE-2025-48913 did not cover every code path that consumes JMS configuration. CVE-2026-44417 identifies an additional path through the same configuration surface that still permits attacker-influenced lookups and downstream object instantiation. The result is the same class of outcome: code execution under the identity of the Apache CXF process.

Root Cause

The root cause is improper input validation of JMS configuration values consumed by Apache CXF. The original remediation hardened one entry point but left a parallel code path that processes the same untrusted input without equivalent restrictions. When an attacker controls JMS connection or destination configuration, that path can dereference attacker-supplied resources during initialization.

Attack Vector

Exploitation requires network access to a CXF deployment that accepts JMS configuration from untrusted principals, and the attacker must hold at least low-privilege access to submit configuration. The attacker supplies crafted JMS configuration that steers the framework into resolving an external resource controlled by the attacker. During resolution, the framework loads and instantiates an object, executing attacker-controlled logic inside the CXF process. No user interaction is required, and successful exploitation yields full impact on confidentiality, integrity, and availability. Technical details are described in the Apache Security Advisory.

Detection Methods for CVE-2026-44417

Indicators of Compromise

• Outbound JNDI, LDAP, or RMI connections originating from the Java process hosting Apache CXF to unexpected hosts.
• Unexpected child processes spawned from the CXF or application server JVM, such as shells or scripting interpreters.
• New or modified JMS endpoint configuration entries submitted by non-administrative users or external integrations.
• Java class loading events referencing remote codebases or unfamiliar JARs at runtime.

Detection Strategies

• Inventory all services using Apache CXF and confirm the version against fixed releases 3.6.11, 4.1.6, and 4.2.1.
• Audit application code and configuration interfaces that expose JMS parameters such as jndiURL, jndiConnectionFactoryName, or jndiDestinationName to untrusted callers.
• Inspect application logs for JMS configuration changes correlated with errors during JNDI lookup or class loading.
• Hunt for process trees where the Java runtime executing CXF spawns command interpreters or network utilities.

Monitoring Recommendations

• Alert on egress connections from application servers to JNDI, LDAP, RMI, or CORBA endpoints outside an approved allowlist.
• Monitor JVM telemetry for remote class loading and serialization events from the javax.naming and JMS provider packages.
• Forward CXF, application server, and JMS broker logs to a centralized analytics platform for correlation across configuration changes and runtime anomalies.

How to Mitigate CVE-2026-44417

Immediate Actions Required

• Upgrade Apache CXF to version 4.2.1, 4.1.6, or 3.6.11 depending on the deployed branch.
• Restrict the ability to configure JMS endpoints to trusted administrators only, and remove configuration endpoints exposed to general users.
• Review existing JMS configurations for unexpected JNDI URLs or destination references and revert unauthorized changes.
• Rotate credentials and secrets that were accessible to the CXF process if exploitation is suspected.

Patch Information

Apache has released patched versions 4.2.1, 4.1.6, and 3.6.11 that close the additional code path missed by the CVE-2025-48913 fix. Upgrade guidance and release notes are available in the Apache Security Advisory. Organizations on the 4.2.x line should move from 4.2.0 to 4.2.1, 4.1.x users should move to 4.1.6, and 3.6.x users should move to 3.6.11.

Workarounds

• Disable the JMS transport in Apache CXF where it is not required.
• Place the application JVM behind egress filtering that blocks JNDI, LDAP, and RMI traffic to untrusted destinations.
• Set the JVM property com.sun.jndi.ldap.object.trustURLCodebase=false and the equivalent RMI flag to prevent remote codebase loading.
• Enforce strict input validation on any management interface that accepts JMS configuration parameters.

# Configuration example: harden the JVM against remote codebase loading
java \
  -Dcom.sun.jndi.ldap.object.trustURLCodebase=false \
  -Dcom.sun.jndi.rmi.object.trustURLCodebase=false \
  -Dcom.sun.jndi.cosnaming.object.trustURLCodebase=false \
  -jar your-cxf-application.jar