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CVE-2026-61634: RabbitMQ Java client accepts broker frames larger than the negotiated AMQP frame_max

• Severity: none (CVSS 0.0 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-18 · updated 2026-10-22
• Weakness: CWE-20

Description

The RabbitMQ Java client library allows Java and JVM-based applications to connect to and interact with RabbitMQ nodes. Prior to 5.33.0, the AMQP connection tuning path records the negotiated AMQP frame_max value, but src/main/java/com/rabbitmq/client/impl/SocketFrameHandler.java and NettyFrameHandlerFactory continue to validate broker-controlled frame payload lengths against maxInboundMessageBodySize because the negotiated limit is not applied consistently through setMaxInboundFramePayloadSize. A malicious or compromised broker can send a method frame larger than the negotiated frame_max during or after connection establishment, causing the client to allocate and decode a protocol-invalid frame instead of rejecting it with MalformedFrameException. The protocol violation can disrupt the affected connection and cause client-side denial of service. This issue is fixed in version 5.33.0.

Affected products

• rabbitmq-java-client: before 5.33.0

References

• https://github.com/rabbitmq/rabbitmq-java-client/commit/08790f09686173eb17b48d08a25edcb32e71a591
• https://github.com/rabbitmq/rabbitmq-java-client/commit/b491075f42e89967610c40beded68d3680cfd472
• https://github.com/rabbitmq/rabbitmq-java-client/pull/1994
• https://github.com/rabbitmq/rabbitmq-java-client/pull/1995
• https://github.com/rabbitmq/rabbitmq-java-client/releases/tag/v5.33.0
• https://github.com/rabbitmq/rabbitmq-java-client/security/advisories/GHSA-5xwg-cfvj-gff5

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