CVE-2026-40473: Apache Camel RCE Vulnerability

CVE-2026-40473 Overview

CVE-2026-40473 is an insecure deserialization vulnerability affecting the camel-mina component in Apache Camel. The MinaConverter.toObjectInput(IoBuffer) type converter wraps an IoBuffer in a java.io.ObjectInputStream without applying any ObjectInputFilter or class-loading restrictions. When a Camel route uses camel-mina as a TCP or UDP consumer and requests conversion to ObjectInput (for example via getBody(ObjectInput.class) or @Body ObjectInput), an attacker sending a crafted serialized Java object over the network to the MINA consumer port can trigger arbitrary code execution in the context of the application during readObject().

Critical Impact

Remote attackers can achieve arbitrary code execution by sending malicious serialized Java objects to exposed MINA consumer ports, potentially leading to complete system compromise.

Affected Products

• Apache Camel versions 3.0.0 through 4.14.5
• Apache Camel versions 4.15.0 through 4.18.1
• Apache Camel version 4.19.0

Discovery Timeline

• April 27, 2026 - CVE-2026-40473 published to NVD
• April 28, 2026 - Last updated in NVD database

Technical Details for CVE-2026-40473

Vulnerability Analysis

This vulnerability stems from unsafe handling of serialized Java objects within the Apache Camel MINA component. The MinaConverter class provides type conversion functionality that transforms IoBuffer data into Java objects. When the toObjectInput() method processes incoming network data, it creates an ObjectInputStream directly from the buffer contents without implementing any deserialization safeguards.

Java deserialization vulnerabilities are particularly dangerous because they allow attackers to instantiate arbitrary classes and execute code during the deserialization process. The readObject() method in Java can trigger a chain of method calls (known as a "gadget chain") that ultimately leads to arbitrary code execution. Without proper filtering mechanisms like ObjectInputFilter, any class available on the classpath can be instantiated.

The network-accessible nature of MINA consumers (supporting both TCP and UDP protocols) significantly increases the attack surface, as remote attackers can directly send malicious payloads without requiring prior authentication in many deployment scenarios.

Root Cause

The root cause is the absence of deserialization controls in the MinaConverter.toObjectInput(IoBuffer) method. The implementation directly wraps incoming network data in an ObjectInputStream without:

• Implementing ObjectInputFilter to restrict which classes can be deserialized
• Applying class-loading restrictions to prevent instantiation of dangerous classes
• Validating the serialized object structure before processing

This design flaw allows untrusted serialized data from the network to be processed as legitimate Java objects, enabling attackers to exploit existing gadget chains in the application's classpath.

Attack Vector

The attack is conducted over the network against applications using camel-mina as a TCP or UDP consumer endpoint. An attacker identifies an exposed MINA consumer port, then crafts a malicious serialized Java object using tools like ysoserial to generate payloads that exploit common gadget chains (such as Commons Collections, Spring, or other libraries present on the target's classpath).

The attacker sends the crafted payload to the MINA consumer port. When the application invokes type conversion to ObjectInput (via methods like getBody(ObjectInput.class)), the MinaConverter.toObjectInput() method processes the malicious data. During the readObject() call, the gadget chain executes, resulting in arbitrary code execution within the application's security context.

Detection Methods for CVE-2026-40473

Indicators of Compromise

• Unexpected outbound network connections from Camel application processes
• Unusual process spawning or command execution traced back to the Java runtime hosting Apache Camel
• Anomalous serialized Java object traffic on MINA consumer ports (TCP/UDP)
• Log entries showing ClassNotFoundException or deserialization errors for suspicious class names commonly used in gadget chains

Detection Strategies

• Monitor network traffic to MINA consumer ports for patterns consistent with Java serialized object headers (0xACED0005)
• Implement application-level logging around type conversion operations in Camel routes
• Deploy runtime application self-protection (RASP) solutions to detect deserialization attacks
• Use Java agent-based monitoring to detect instantiation of known dangerous classes during deserialization

Monitoring Recommendations

• Enable verbose logging for Apache Camel routes using camel-mina components
• Configure network intrusion detection systems to alert on Java serialization magic bytes in inbound traffic
• Monitor for suspicious Java class loading events, particularly classes from common gadget chain libraries
• Implement endpoint detection for signs of post-exploitation activity such as reverse shells or data exfiltration

How to Mitigate CVE-2026-40473

Immediate Actions Required

• Upgrade Apache Camel to version 4.20.0 or later immediately
• For users on the 4.14.x LTS release stream, upgrade to version 4.14.6
• For users on the 4.18.x release stream, upgrade to version 4.18.2
• If immediate upgrade is not possible, disable or restrict network access to MINA consumer ports

Patch Information

Apache has released fixed versions that address this vulnerability by implementing proper deserialization controls. Users should consult the Apache Camel CVE-2026-40473 Advisory for complete patch details and upgrade instructions.

Workarounds

• Implement network-level access controls to restrict which hosts can connect to MINA consumer ports
• Deploy a Web Application Firewall (WAF) or network filter to inspect and block traffic containing Java serialization signatures
• If ObjectInput conversion is not required, modify Camel routes to avoid using getBody(ObjectInput.class) or @Body ObjectInput annotations
• Consider implementing a custom ObjectInputFilter at the JVM level using the -Djdk.serialFilter system property to restrict deserializable classes globally

# Example: Restrict deserialization at JVM level (temporary mitigation)
# Add to Java startup options
-Djdk.serialFilter=!*
# Or allow only specific safe classes
-Djdk.serialFilter=java.base/*;!*