# RabbitMQ amqp091-go: Denial of Service via Sub-Spec Frame Size Negotiation

Advisory record · `GHSA-xwwf-m8fg-p9q2`

- **Identifiers:** `GHSA-xwwf-m8fg-p9q2` · `CVE-2026-77403` · `GO-2026-6503`
- **State:** Confirmed
- **Severity:** CVSS 8.9 High
- **Critical:** No
- **Weakness (CWE):** [CWE-770](https://cwe.mitre.org/data/definitions/770.html)
- **Tags:** [Denial of service](https://agentprime.io/advisories/tag/dos.md)
- **Published:** 17 Sept 2026
- **Updated:** 1 Oct 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 17 Sept 2026, 17:03 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `github.com/rabbitmq/amqp091-go` (Go): affected `<1.13.0`; fixed in `1.13.0`

## Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

> GHSA-xwwf-m8fg-p9q2: the Go package github.com/rabbitmq/amqp091-go before 1.13.0 does not enforce the AMQP minimum frame size of 4096 bytes during connection negotiation, so it accepts a server-advertised FrameMax as low as 1 byte. An attacker who controls or intercepts the broker a client connects to can force every message to be split into tiny frames, exhausting CPU and freezing the application. Upgrade to version 1.13.0 or later.

Written 1 Nov 2026.

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 8.9 High, CVSS 4.0: `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`, from CNA (GitHub_M)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0052, the 44th percentile, on 8 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 14:12 UTC: First seen by agentprime
- 31 Oct 2026, 14:12 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-xwwf-m8fg-p9q2)

## Sources

- [GitHub Advisory Database: GHSA-xwwf-m8fg-p9q2](https://github.com/advisories/GHSA-xwwf-m8fg-p9q2)
- [OSV: GHSA-xwwf-m8fg-p9q2](https://osv.dev/vulnerability/GHSA-xwwf-m8fg-p9q2)
- <https://github.com/rabbitmq/amqp091-go/security/advisories/GHSA-xwwf-m8fg-p9q2>
- <https://nvd.nist.gov/vuln/detail/CVE-2026-77403>
- <https://github.com/rabbitmq/amqp091-go/pull/353>
- <https://github.com/rabbitmq/amqp091-go/commit/2e0a919b89f337dbf58db2bb34ab206dac354a06>
- <https://github.com/rabbitmq/amqp091-go>
- <https://github.com/rabbitmq/amqp091-go/releases/tag/v1.13.0>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-xwwf-m8fg-p9q2>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

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The web page: <https://agentprime.io/advisories/GHSA-xwwf-m8fg-p9q2/>. Everything for agents: <https://agentprime.io/llms.txt>.