PatchSiren cyber security CVE debrief
CVE-2026-57216 rabbitmq CVE debrief
CVE-2026-57216 is a medium-severity vulnerability in RabbitMQ that allows for authentication bypass under certain conditions involving PROXY-protocol paths and loopback-bound listeners. The issue arises from the way RabbitMQ handles authentication for AMQP 0-9-1, AMQP 1.0, and Stream Protocol, specifically using listener-side socket addresses instead of the real client source. This allows loopback-restricted users like 'guest' to connect remotely. Users of RabbitMQ, particularly those with loopback-restricted users or relying on PROXY-protocol for traffic authentication, should be aware and take action.
- Vendor
- rabbitmq
- Product
- rabbitmq-server
- CVSS
- MEDIUM 6.8
- CISA KEV
- Not listed in stored evidence
- Original CVE published
- 2026-07-10
- Original CVE updated
- 2026-07-10
- Advisory published
- 2026-07-10
- Advisory updated
- 2026-07-10
Who should care
Users of RabbitMQ, particularly those who have loopback-restricted users or rely on PROXY-protocol for traffic authentication, should be aware of this vulnerability. This includes administrators of RabbitMQ servers, especially in environments where remote access is common, and security teams responsible for vulnerability management.
Technical summary
The vulnerability exists in RabbitMQ versions prior to 3.13.15, 4.0.20, 4.1.11, and 4.2.6. It is caused by the incorrect use of listener-side socket addresses in loopback checks, rather than the actual client source addresses. This can allow unauthorized access by bypassing loopback restrictions for certain users, such as 'guest', under specific conditions involving PROXY-protocol paths and loopback-bound listeners.
Defensive priority
Medium priority should be given to updating RabbitMQ to a secure version, as the vulnerability allows for authentication bypass under specific conditions. Defenders should focus on patching, reviewing loopback restrictions, and monitoring for unusual activity.
Recommended defensive actions
- Update RabbitMQ to version 3.13.15, 4.0.20, 4.1.11, or 4.2.6, or later.
- Review and adjust loopback restrictions for RabbitMQ users.
- Monitor for unusual authentication attempts.
- Confirm whether affected RabbitMQ deployments exist in managed environments and assign an owner for follow-up.
- Review compensating controls for exposed systems while remediation is scheduled and verified.
- Check relevant monitoring, detection, and logs for exposed assets that need extra review.
- Track exceptions, retest remediated assets, and close the item only after evidence is documented.
Evidence notes
The CVE record and NVD detail provide information on the vulnerability. Additional details can be found in the RabbitMQ server GitHub commits and security advisory. Evidence is limited to public sources and may not reflect the full scope or impact of the vulnerability. Defenders should verify affected systems and review vendor guidance for specific exposure.
Official resources
AI-assisted PatchSiren debrief based on the supplied source corpus. The CVE record was published on 2026-07-10T21:16:58.677Z and has not been modified since then.