CVE-2026-63337 PUBLISHED

RabbitMQ Java client: Unvalidated Class.forName in JSON-RPC ProcedureDescription enables arbitrary class loading

Assigner: GitHub_M
Reserved: 16.07.2026 Published: 18.08.2026 Updated: 18.08.2026

The RabbitMQ Java client library allows Java and JVM-based applications to connect to and interact with RabbitMQ nodes. Prior to 5.33.0, com.rabbitmq.tools.jsonrpc.ProcedureDescription receives a javaReturnType value in an untrusted system.describe response and passes it through JSONUtil.tryFill, setJavaReturnType, and computeReturnTypeAsJavaClass to Class.forName(javaReturnType) with initialization enabled. An attacker able to answer the JsonRpcClient request through a shared broker or network interception can select a class already present in the victim JVM and trigger its static initializer, while JsonRpcClient.java later passes getReturnType output to mapper.parse and may also create type confusion. Successful exploitation can affect confidentiality, integrity, and availability in the client process. This issue is fixed in version 5.33.0.

Metrics

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:H/VI:H/VA:H/SC:L/SI:L/SA:L
CVSS Score: 7.5

Product Status

Vendor rabbitmq
Product rabbitmq-java-client
Versions
  • Version < 5.33.0 is affected

References

Problem Types

  • CWE-470: Use of Externally-Controlled Input to Select Classes or Code ('Unsafe Reflection') CWE