CVE-2026-61634: RabbitMQ Java client protocol violation on oversized frames

CVE-2026-61634 · Severity: medium · CVSS 4 · Published 2026-08-18

The RabbitMQ Java client is a library used by Java applications to communicate with RabbitMQ message brokers. The vulnerability allows a rogue or compromised broker to send frames larger than the size limit negotiated during connection setup. While the client records the negotiated frame_max value, it validates incoming payloads against a much larger internal limit instead, allowing protocol violations to go undetected. This could enable a malicious broker to crash clients or trigger unexpected behavior.

Technologies: com.rabbitmq:amqp-client (Maven). Vendors: Maven.

Quick answers

Is CVE-2026-61634 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-61634 being exploited in the wild.
How severe is CVE-2026-61634?
Medium severity, with a CVSS score of 4, published 18 August 2026.
Which products and versions are affected?
com.rabbitmq:amqp-client (Maven) < 5.33.0, ECOSYSTEM:introduced=0,fixed=5.33.0.
Is there a fix for CVE-2026-61634?
Yes. com.rabbitmq:amqp-client (Maven): upgrade to 5.33.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-61634 attacked?
It is attacked over the network, in a software library.
Am I affected by CVE-2026-61634?
Check whether you run com.rabbitmq:amqp-client (Maven) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • com.rabbitmq:amqp-client (Maven): upgrade to 5.33.0 or later
    # set com.rabbitmq:amqp-client to 5.33.0 in your pom.xml or build.gradle

Technical details

The vulnerability is an improper input validation flaw (CWE-20) in the RabbitMQ Java client's socket inbound frame reader. During AMQP 0-9-1 connection tuning, the client correctly records the broker-negotiated frame_max size. However, when the socket reader validates incoming method frame payloads, it incorrectly checks them against maxInboundMessageBodySize (a much larger limit) instead of frame_max. This allows a broker to send a method frame with a payload exceeding frame_max, have it allocated and decoded, and complete the connection handshake instead of being rejected as a protocol violation. The attack requires network access to communicate with the client as a broker peer, with high attack complexity. The patch (version 5.33.0 and later) corrects the frame validation logic to properly enforce the negotiated frame_max limit.

Affected products

  • RabbitMQ Java client < 5.33.0

Identifiers

  • CVE-2026-61634
  • GHSA-5xwg-cfvj-gff5

Timeline

  • 2026-07-09: disclosed: Published in GitHub Advisory Database
  • 2026-07-09: patched: Fix available in version 5.33.0
  • 2026-08-18: advisory: Advisory GHSA-5xwg-cfvj-gff5 published

References

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