CVE-2026-63335

RabbitMQ Java client malformed body frame triggers raw command assembler exception

MEDIUM
6.3
CVSS Score
Published: August 18, 2026 at 04:20 PM UTC
Updated: October 22, 2026 at 10:10 PM UTC
1 product affected across 1 vendorRabbitmq Java Client

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Severity
MEDIUM6.3
Exploit prediction
EPSS 0.5%
SSVC
PoC

Description

The RabbitMQ Java client library allows Java and JVM-based applications to connect to and interact with RabbitMQ nodes. Prior to 5.31.0, inbound AMQP command assembly in src/main/java/com/rabbitmq/client/impl/CommandAssembler.java processes a content-bearing method and header whose remainingBodyBytes value is smaller than a following AMQP.FRAME_BODY payload. CommandAssembler.consumeBodyFrame subtracts the peer-controlled payload length before validating that it fits, drives remainingBodyBytes negative, and throws a raw UnsupportedOperationException instead of MalformedFrameException. A malicious or compromised broker peer can send this malformed sequence on an open nonzero channel to terminate frame processing and close the client connection, causing denial of service for work using that connection. This issue is fixed in version 5.31.0.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 5.31.0
Affected range stops below 5.31.0, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

SSVC — Action Prioritization

SSVCPoCNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

6.3MEDIUMGitHub_M
Vector?

Quick Info

StatusAWAITING ANALYSIS
CWE
CWE-20

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