Description

Potential for deserialization of untrusted types in Spring Cloud Stream. Spring Cloud Stream 5.0.0 - 5.0.2 Spring Cloud Stream 4.3.0 - 4.3.3 Spring Cloud Stream 4.2.0 - 4.2.6

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "3.1",
  "pubDate": "2026-08-27T20:17:56.990Z",
  "pubdate": "2026-08-27T20:17:56.990Z",
  "executiveSummary": "This vulnerability involves the insecure deserialization of untrusted data types within the Spring Cloud Stream framework, specifically affecting versions 5.0.0-5.0.2, 4.3.0-4.3.3, and 4.2.0-4.2.6.\nThe flaw allows an attacker to manipulate serialized objects handled by the framework to execute arbitrary code or perform unauthorized actions with the privileges of the application process.\nThe vulnerability originates from the lack of strict type validation during the deserialization process, enabling the processing of malicious payloads.\nThe impact is critical, as successful exploitation may lead to Remote Code Execution (RCE), potentially resulting in full system compromise, data exfiltration, or denial of service.\nExploitation requires an attacker to be able to influence the input data stream processed by the vulnerable Spring Cloud Stream component, typically involving interaction with message brokers or external data feeds.\nThere are no specific authentication requirements for the application itself, as the exploitation is contingent upon the attacker's ability to inject malicious serialized objects into the expected data flow.",
  "technicalDetails": "The vulnerability arises from the failure of Spring Cloud Stream to adequately sanitize or restrict the types permitted for deserialization when processing incoming message payloads.\nIn Java-based applications, deserialization is the process of converting a stream of bytes back into an object. When the framework attempts to instantiate these objects without verifying that the class being deserialized is expected or safe, it becomes susceptible to gadget chain attacks.\nAn attacker can craft a malicious serialized object, often utilizing known gadget chains (classes available in the application's classpath that perform dangerous operations during deserialization, such as executing commands or loading classes).\nWhen the Spring Cloud Stream framework processes this malicious payload, the standard ObjectInputStream or equivalent deserialization mechanism reconstructs the object graph.\nDuring this process, the framework invokes methods on the reconstructed objects. If the payload contains an engineered gadget chain, the recursive execution of 'readObject', 'readResolve', or similar methods triggers the execution of arbitrary code within the context of the JVM.\nAffected versions include Spring Cloud Stream 5.0.0 - 5.0.2, 4.3.0 - 4.3.3, and 4.2.0 - 4.2.6. The vulnerability exists within the component responsible for message conversion and payload handling.\nAttack flow: 1. An attacker identifies a message ingestion point managed by Spring Cloud Stream. 2. The attacker crafts a malicious serialized payload designed to leverage gadget chains present in the application's classpath. 3. The payload is sent to the message broker or input channel utilized by the application. 4. The application receives the payload and the framework automatically attempts to deserialize it. 5. The gadget chain executes, leading to arbitrary code execution on the server hosting the application.\nThe network exposure is defined by the accessibility of the message broker or input channels to the attacker. If these channels are exposed to untrusted sources, the risk is significantly elevated. Post-exploitation impact includes complete control over the application process, unauthorized access to internal resources, and potential lateral movement within the network infrastructure."
}