Bug 2518029 (CVE-2026-63337)

Summary: CVE-2026-63337 com.rabbitmq/amqp-client: RabbitMQ Java client: Arbitrary class loading via unvalidated input in JSON-RPC.
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedCC: fmongiar, gmalinko, janstey, jnethert, pdelbell, rstepani
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the RabbitMQ Java client library. A remote attacker, by intercepting or answering a JsonRpcClient request, could provide a malicious javaReturnType value. This unvalidated input is then used in Class.forName, allowing the attacker to load an arbitrary class already present in the victim's Java Virtual Machine (JVM) and trigger its static initializer. Successful exploitation of this vulnerability could lead to arbitrary code execution, impacting the confidentiality, integrity, and availability of the client process.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-08-18 16:31:53 UTC 
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.