Rabbitmq server: RabbitMQ is a messaging and streaming broker. (CVE-2026-67404)
Description
RabbitMQ versions prior to 3.13.15, 4.0.20, 4.1.11, 4.2.6, and 4.3.0 have a vulnerability in the OAuth2 plugin where, if no CA bundle is available, the ssl_options/1 function falls back to no certificate verification without warning. This allows a man-in-the-middle attacker to forge JWKS responses and cause the broker to accept arbitrary JWTs. The vulnerability requires the OAuth2 plugin to be in use without a configured cacertfile and an empty or unreadable OS CA bundle, conditions common in minimal container environments. The issue is fixed in the stated versions.
CVSS v4.0
Affected software
pkg:deb/ubuntu/rabbitmq-server?arch=source&distro=esm-infra-legacy/xenialpkg:deb/ubuntu/rabbitmq-server?arch=source&distro=esm-infra/bionicpkg:deb/ubuntu/rabbitmq-server?arch=source&distro=esm-infra/focalpkg:deb/ubuntu/rabbitmq-server?arch=source&distro=jammypkg:deb/ubuntu/rabbitmq-server?arch=source&distro=noblepkg:deb/ubuntu/rabbitmq-server?arch=source&distro=resoluteRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
RabbitMQ is a messaging and streaming broker. In affected versions prior to 3.13.15, 4.0.20, 4.1.11, 4.2.6, and 4.3.0, when no CA bundle is available, the ssl_options/1 function falls back to [{verify, verify_none}] without warning. This fallback disables SSL certificate verification. An attacker positioned as a network man-in-the-middle can exploit this by forging the JWKS response, leading the broker to accept arbitrary JWTs. Preconditions include use of the OAuth2 plugin without a configured cacertfile and an empty or unreadable OS CA bundle, such as in minimal container environments. The vulnerability is addressed in the specified fixed versions.
Potential Impact
An attacker with man-in-the-middle network position can forge JWKS responses, causing the RabbitMQ broker to accept arbitrary JWTs. This can lead to unauthorized access or privilege escalation within the broker environment. The vulnerability requires specific conditions: use of the OAuth2 plugin without a configured cacertfile and an empty or unreadable OS CA bundle. There are no known exploits in the wild at this time.
Mitigation Recommendations
A fix is available and has been released in RabbitMQ versions 3.13.15, 4.0.20, 4.1.11, 4.2.6, and 4.3.0. Users should upgrade to these or later versions to remediate the vulnerability. Additionally, ensuring that a valid CA bundle is configured and accessible can prevent the fallback to no verification. Refer to the official Ubuntu security notice USN-8933-1 for detailed patch information.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- UBUNTU-CVE-2026-67404
- Osv Schema Version
- 1.7.0
- Ecosystems
- ["Ubuntu:Pro:16.04:LTS","Ubuntu:Pro:18.04:LTS","Ubuntu:Pro:20.04:LTS","Ubuntu:22.04:LTS","Ubuntu:24.04:LTS","Ubuntu:26.04:LTS"]
- Cvss Version
- 4.0
- State
- PUBLISHED
Patch Information
Threat ID: 6ad3f5a92cdf04f6566627e4
Added to database: 10/17/2026, 22:24:41 UTC
Last enriched: 10/17/2026, 23:57:04 UTC
Last updated: 10/17/2026, 23:57:04 UTC
Views: 2
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