---
id: "CVE-2026-77411"
kind: "vulnerability"
aliases: ["CVE-2026-77411", "GHSA-c5pq-fr2g-9jpf", "GO-2026-6496"]
title: "RabbitMQ amqp091-go: Protocol Desynchronization and Frame Injection via Integer Overflow in readLongstr in github.com/rabbitmq/amqp091-go"
severity: "critical"
cvss: 9.5
epss: 0.00524
exploited: false
status: "open"
category: "package"
products: [{"name": "github.com/rabbitmq/amqp091-go", "fixed": ["1.13.0"], "affected": "< 1.13.0", "ecosystem": "go"}]
ecosystems: ["go"]
tags: ["amqp", "go", "package", "rabbitmq"]
not_affected_if: ["broker-trusted", "version-1.13.0-or-later"]
published_at: "2026-09-16T15:17:50+00:00"
first_seen_at: "2026-10-23T19:13:08+00:00"
updated_at: "2026-10-23T21:43:45+00:00"
sources: [{"source": "govuln", "url": "https://pkg.go.dev/vuln/GO-2026-6496", "first_seen_at": "2026-10-23T19:13:08+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2026-77411", "first_seen_at": "2026-10-23T19:13:43+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-77411", "first_seen_at": "2026-10-23T19:35:23+00:00"}]
---

# RabbitMQ amqp091-go: Protocol Desynchronization and Frame Injection via Integer Overflow in readLongstr in github.com/rabbitmq/amqp091-go

amqp091-go is a Go AMQP 0.9.1 client whose readLongstr returns success on an oversized length field, so table parsing continues from the wrong offset. A malicious or compromised RabbitMQ broker can make the client misparse following bytes as fields or frames, breaking connection integrity and availability.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- go:github.com/rabbitmq/amqp091-go affected < 1.13.0 fixed 1.13.0

## How to check

Run `go list -m github.com/rabbitmq/amqp091-go` and check whether the version is below 1.13.0.

## Fix

Upgrade github.com/rabbitmq/amqp091-go to 1.13.0 or later.

## Timeline

- 2026-10-23T19:13:08+00:00 govuln https://pkg.go.dev/vuln/GO-2026-6496
- 2026-10-23T19:13:43+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2026-77411
- 2026-10-23T19:35:23+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-77411

## From the sources

RabbitMQ amqp091-go is a Go AMQP 0.9.1 client. Prior to 1.13.0, readLongstr in read.go returns an empty string and a nil error when a declared AMQP longstr length exceeds 0x7FFFFFFF instead of returning ErrSyntax. The function leaves the declared field bytes unread, while readTable treats the operation as successful and continues parsing from the wrong offset. A malicious or compromised broker can provide an oversized longstr in a table field and desynchronize subsequent AMQP parsing, causing attacker-controlled trailing bytes to be interpreted as later fields or frames and disrupting connection integrity and availability. This issue is fixed in version 1.13.0.

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