Bug 2535498 (CVE-2026-77403)

Summary: CVE-2026-77403 github.com/rabbitmq/amqp091-go: RabbitMQ amqp091-go: Denial of Service via AMQP frame size negotiation
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: aazores, cmah, dhanak, doconnor, drosa, dsimansk, eaguilar, ebaron, eglynn, gparvin, jbalunas, jjoyce, jmatsuok, jpretori, jschluet, jtolenti, kingland, lhh, mburns, mgarciac, mnovotny, pjindal, rhaigner, sausingh, tsze
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in RabbitMQ amqp091-go, a Go AMQP 0.9.1 client. A malicious or compromised AMQP broker can exploit this by advertising an extremely small frame size during connection negotiation. This can lead to excessive fragmentation of client publications, consuming significant CPU resources and potentially causing a Denial of Service (DoS) by stalling the client or its host.
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Description OSIDB Bzimport 2026-09-16 14:54:18 UTC 
RabbitMQ amqp091-go is a Go AMQP 0.9.1 client. Prior to 1.13.0, Connection.openTune in connection.go accepts a server-advertised FrameMax below the AMQP frameMinSize value of 4096 bytes because the connection negotiation loop does not enforce the protocol minimum. A malicious or compromised AMQP broker can therefore advertise an extremely small FrameMax, causing later client publications to be fragmented into excessive numbers of frames and write operations. This can consume CPU and stall the client or its host. This issue is fixed in version 1.13.0.