# CVE-2026-57216: Auth bypass in rabbitmq-server

> Remote attackers can bypass loopback restrictions to connect as guest users via trusted proxy paths in RabbitMQ.

- **Severity:** Medium 6.8 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 10 Jul 2026
- **Updated:** 13 Jul 2026
- **Also known as:** AZL-92349, DEBIAN-CVE-2026-57216, GHSA-36m6-588r-vqcw, UBUNTU-CVE-2026-57216

## What is CVE-2026-57216?

CVE-2026-57216 is a medium-severity authentication bypass vulnerability in Broadcom Rabbitmq Server, published on 10 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

RabbitMQ is a messaging and streaming broker. Prior to 3.13.15, 4.0.20, 4.1.11, and 4.2.6, AMQP 0-9-1, AMQP 1.0, and Stream Protocol authentication can allow a loopback-restricted user such as guest to connect remotely when traffic is accepted through a trusted PROXY-protocol path and the backend listener is loopback-bound because the loopback check uses the listener-side socket address instead of the real client source. This issue is fixed in versions 3.13.15, 4.0.20, 4.1.11, and 4.2.6.

Weakness: CWE-287 (Improper Authentication)

## Which versions are affected by CVE-2026-57216?

It affects 1 product.


Products: Broadcom Rabbitmq Server.

## How do I fix CVE-2026-57216?

Upgrade to a fixed version.

## Is CVE-2026-57216 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-57216 exists.

## Other vulnerabilities in Broadcom Rabbitmq Server

- [CVE-2016-9877](https://insights.sbomify.com/CVE-2016-9877/): Auth bypass in Pivotal RabbitMQ 3.x before 3.5.8 and 3.6.x before 3.6.6; RabbitMQ for PCF 1.5.x before 1.5.20, 1.6.x before 1.6.12 and 1.7.x before 1.7.7 (critical 9.8)
- [CVE-2026-67404](https://insights.sbomify.com/CVE-2026-67404/): RabbitMQ: OAuth2 silent verify_none fallback for JWKS fetch (critical 9.2)
- [CVE-2026-67231](https://insights.sbomify.com/CVE-2026-67231/): RabbitMQ: Trust-store whitelist by Issuer+Serial only (critical 9.1)
- [CVE-2026-57219](https://insights.sbomify.com/CVE-2026-57219/): Information disclosure in rabbitmq-server (high 8.7)
- [CVE-2026-67236](https://insights.sbomify.com/CVE-2026-67236/): RabbitMQ: Plaintext username:password stored in an insecure cookie after successful POST /login (high 8.2)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-57216 and fix it if it is affected.

What it is: CVE-2026-57216 is a medium-severity authentication bypass vulnerability in Broadcom Rabbitmq Server, published on 10 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-57216 exists.

Affected product: Broadcom Rabbitmq Server. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-57216/ (Markdown: https://insights.sbomify.com/CVE-2026-57216/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-57216
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-57216
- OSV: https://osv.dev/vulnerability/CVE-2026-57216

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-57216/
Summaries are generated and may contain mistakes; the official description above is the record.