---
title: "CVE-2026-77408: RabbitMQ amqp091-go: Silent Data Truncation and State Corruption via Shortstr Integer Overflow"
url: https://erroneo.us/security/cve/CVE-2026-77408/
description: "CVE-2026-77408 (github.com/rabbitmq/amqp091-go (Go)): RabbitMQ amqp091-go is a Go AMQP 0.9.1 client. Prior to 1.13.0, the writeShortstr function in write.go…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-09-16
date_modified: 2026-09-17
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-77408"
kev: false
cvss: 9.1
epss: 0.00524
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-77408: RabbitMQ amqp091-go: Silent Data Truncation and State Corruption via Shortstr Integer Overflow

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 0.5% , percentile 44: FIRST’s model estimates a 0.5% chance of exploitation activity in the next 30 days, higher than 44% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes github.com/rabbitmq/amqp091-go (Go) < 1.13.0, fixed in 1.13.0 . Check your lockfile, including transitive dependencies.

## What it is

RabbitMQ amqp091-go is a Go AMQP 0.9.1 client. Prior to 1.13.0, the writeShortstr function in write.go casts the byte length of AMQP shortstr property values to uint8 without first rejecting values longer than 255 bytes. An application that accepts an oversized CorrelationId, ReplyTo, MessageId, Expiration, UserId, AppId, ContentType, ContentEncoding, or Type value can therefore serialize a wrapped length and only a truncated prefix, while reporting no error. The resulting silent metadata corruption can break request and reply correlation, routing, tracing, and downstream message processing. This issue is fixed in version 1.13.0.

## Affected packages

- Go `github.com/rabbitmq/amqp091-go` < 1.13.0 → fixed: 1.13.0

## Affected products (CVE record)

- rabbitmq amqp091-go: < 1.13.0

## Severity

- GitHub_M CVSS 4.0: 9.1 `CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:H/VA:H/SC:L/SI:H/SA:L`
- GitHub CVSS 4.0: 9.1 `CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:H/VA:H/SC:L/SI:H/SA:L`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none , automatable yes , technical impact partial .
- FIRST EPSS (model of 2026-10-21): 0.52% probability of exploitation activity in the next 30 days; percentile 44.

## Sources

- [GitHub Advisory GHSA-j497-x9hr-x34x](https://github.com/advisories/GHSA-j497-x9hr-x34x)
- [CVE.org record CVE-2026-77408](https://www.cve.org/CVERecord?id=CVE-2026-77408)
- [NVD entry CVE-2026-77408](https://nvd.nist.gov/vuln/detail/CVE-2026-77408)
- [github.com](https://github.com/rabbitmq/amqp091-go/security/advisories/GHSA-j497-x9hr-x34x)
- [github.com](https://github.com/rabbitmq/amqp091-go/pull/354)
- [github.com](https://github.com/rabbitmq/amqp091-go/commit/6959423aa2784a1971e399175dfb2065dea0f3b0)
- [github.com](https://github.com/rabbitmq/amqp091-go/releases/tag/v1.13.0)

---
Source page: https://erroneo.us/security/cve/CVE-2026-77408/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt