CVE-2026-63337
HighCVSS 7.5Exploitation Probability (EPSS)
Low risk25th percentile - higher than 25% of all known CVEs
Summary
RabbitMQ Java client library before 5.33.0 passes a javaReturnType value from an untrusted system.describe response to Class.forName with initialization enabled. An attacker able to answer the JsonRpcClient request can select a class already present in the victim JVM and trigger its static initializer, potentially affecting confidentiality, integrity, and availability in the client process.
Risk Assessment
An attacker can exploit the vulnerability to execute code in the client context, potentially compromising data security and application stability.
Recommendation
Upgrade the RabbitMQ Java client library to version 5.33.0 or later.
Original NVD description (English source)
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.