🟠 High | Source: Microsoft Security Response Center
A vulnerability in RabbitMQ (CVE-2026-57216) allows remote attackers to establish guest sessions by bypassing loopback enforcement checks across the AMQP 1.0, AMQP 0-9-1, and Stream protocols. By default, RabbitMQ restricts guest user access to loopback (localhost) connections only, but this flaw undermines that control. This matters because it could grant unauthenticated or low-privilege remote access to RabbitMQ brokers that were assumed to be protected by loopback restrictions.
Security Architect’s Take: Audit all RabbitMQ deployments — particularly those hosted on Azure or within Azure-adjacent infrastructure — and apply vendor patches immediately; additionally, enforce network-level controls (e.g. NSGs, private endpoints) to restrict RabbitMQ listener ports and do not rely solely on RabbitMQ’s built-in loopback enforcement as a security boundary.
Original advisory: CVE-2026-57216 RabbitMQ: AMQP 1.0, AMQP 0-9-1, Stream Protocol loopback enforcement can lead to remote guest sessions due to listener-address loopback checks