# CVE-2026-67409: RabbitMQ: JWKS Fetch Ignores HTTP Response Status Code - Signing Key Destruction Causes Authentication DoS

CVE-2026-67409 is fixed in rabbitmq-server on 1 platform, first by rabbitmq-server 4.0.5-10ubuntu5.2, released September 25, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-67409
- Priority: Routine
- CVSS: 6.5 (Important)
- EPSS: 0.0042
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 25, 2026
- Weakness: Unchecked Return Value
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-67409

## Description

RabbitMQ is a messaging and streaming broker. From 3.13.0 until 4.3.3, 4.2.9, 4.1.14, 4.0.23, and 3.13.18, JWKS Fetch Ignores HTTP Response Status Code - Signing Key Destruction Causes Authentication DoS (CWE-252). the JWKS key fetching mechanism in uaajwt.erl does not validate the HTTP response status code when downloading signing keys from the OAuth2 provider's JWKS endpoint. Non-200 responses (including 4xx and 5xx errors) are processed identically to successful responses. When the JWKS endpoint returns an error response with a valid-JSON body that lacks a keys field, all previously cached signing keys are destroyed, causing a persistent authentication denial of Files: deps/rabbitmqauthbackendoauth2/src/uaajwt.erl, lines 50-63 deps/rabbitmqauthbackendoauth2/src/uaajwks.erl, lines 5-7 deps/rabbitmqauthbackendoauth2/src/rabbitoauth2provider.erl, lines 98-107 Bug 1: HTTP status code ignored (uaajwt.erl:50-63): The Erlang httpc module returns {ok, {{HttpVersion, StatusCode, ReasonPhrase}, Headers, Body}}. The pattern {ok, {, , JwksBody}} matches ANY successful HTTP transaction Persistent authentication DoS: Once keys are destroyed, ALL OAuth2/JWT authentication fails for all users until a new successful JWKS refresh occurs Amplification: A single attacker can deny access to all legitimate OAuth2 users across the entire RabbitMQ. This issue is fixed in versions 4.3.3, 4.2.9, 4.1.14, 4.0.23, and 3.13.18.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | rabbitmq-server Debian 14 | 4.3.6-1 | [DEBIAN-CVE-2026-67409](https://patchblox.com/security/data/fix/linux/debian-cve-2026-67409.md) | Oct 10, 2026 |
| Linux | rabbitmq-server Ubuntu 18.04.6 LTS (bionic) | 3.6.10-1ubuntu0.5+esm1 | [rabbitmq-server 3.6.10-1ubuntu0.5+esm1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-rabbitmq-server-3.6.10-1ubuntu0.5-esm1.md) | Oct 19, 2026 |
| Linux | rabbitmq-server Ubuntu 20.04 LTS (focal) | 3.8.3-0ubuntu0.3+esm2 | [rabbitmq-server 3.8.3-0ubuntu0.3+esm2](https://patchblox.com/security/data/fix/linux/ubuntu-focal-rabbitmq-server-3.8.3-0ubuntu0.3-esm2.md) | Oct 19, 2026 |
| Linux | rabbitmq-server Ubuntu 22.04.1 LTS (jammy) | 3.9.27-0ubuntu0.6 | [rabbitmq-server 3.9.27-0ubuntu0.6](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-rabbitmq-server-3.9.27-0ubuntu0.6.md) | Oct 19, 2026 |
| Linux | rabbitmq-server Ubuntu 24.04.5 LTS (noble) | 3.12.1-1ubuntu1.7 | [rabbitmq-server 3.12.1-1ubuntu1.7](https://patchblox.com/security/data/fix/linux/ubuntu-noble-rabbitmq-server-3.12.1-1ubuntu1.7.md) | Oct 19, 2026 |
| Linux | rabbitmq-server Ubuntu 26.04.1 LTS (resolute) | 4.0.5-10ubuntu5.2 | [rabbitmq-server 4.0.5-10ubuntu5.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-rabbitmq-server-4.0.5-10ubuntu5.2.md) | Sep 25, 2026 |

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Data as of 2026-11-08T00:53:09Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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