---
id: CVE-2026-77403
title: RabbitMQ amqp091-go is a Go AMQP 0.9.1 client
summary: >-
  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 en…
severity: high
cvss: 8.9
cvssVector: 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H'
cwe:
  - CWE-770
  - CWE-839
vendor: rabbitmq
product: amqp091-go
affected:
  - amqp091-go < 1.13.0
patched:
  - github.com/rabbitmq/amqp091-go 1.13.0
published: '2026-09-16'
updated: '2026-09-23'
sourceUpdated: '2026-09-23T18:19:19.803'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-77403'
references:
  - url: >-
      https://github.com/rabbitmq/amqp091-go/commit/2e0a919b89f337dbf58db2bb34ab206dac354a06
    label: security-advisories@github.com
  - url: 'https://github.com/rabbitmq/amqp091-go/pull/353'
    label: security-advisories@github.com
  - url: 'https://github.com/rabbitmq/amqp091-go/releases/tag/v1.13.0'
    label: security-advisories@github.com
  - url: >-
      https://github.com/rabbitmq/amqp091-go/security/advisories/GHSA-xwwf-m8fg-p9q2
    label: security-advisories@github.com
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-77403.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-77403'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2535498'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-77403'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-77403'
  - url: 'https://github.com/advisories/GHSA-xwwf-m8fg-p9q2'
  - url: 'https://github.com/rabbitmq/amqp091-go'
  - url: 'https://access.redhat.com/errata/RHSA-2026:68290'
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
  - ghsa
  - go
  - osv
epss: 0.00411
epssPercentile: 0.35104
aliases:
  - GHSA-xwwf-m8fg-p9q2
ecosystem: go
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-16T15:42:59.993831Z'
cvssSource: cna
scores:
  cna: 8.9
  vendor: 7.5
ingestedAt: '2026-09-16T14:57:28.049Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Package advisory (CVE-2026-77403)

Affected packages:

- `github.com/rabbitmq/amqp091-go < 1.13.0`

Patched in:

- `github.com/rabbitmq/amqp091-go 1.13.0`

Source: https://github.com/advisories/GHSA-xwwf-m8fg-p9q2

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Cryostat 4, Custom Metric Autoscaler operator for Red Hat Openshift, Multicluster Global Hub, OpenShift Serverless, Red Hat Advanced Cluster Management for Kubernetes 2, Red Hat OpenStack Platform 18.0, … · no fix planned: Cryostat 4, Custom Metric Autoscaler operator for Red Hat Openshift, Multicluster Global Hub, OpenShift Serverless, … · updated 2026-09-21 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-77403.json)
- **RHSA-2026:68290** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-09-16 · [advisory](https://access.redhat.com/errata/RHSA-2026:68290)