Advisory ID:

TNZ-2026-0337

Severity:

[Medium]

Issue Date:

2026-05-06

Updated on:

2026-07-23

Synopsis

RabbitMQ MQTT Topic Permission Authorization Bypass

RabbitMQ's MQTT plugin allows for topic-level authorization using regular expressions with variable substitution. Administrators can create patterns such as ^{clientid}-sensors$ to restrict user access to topics that include their client ID. However, the clientid is provided by the user in the MQTT CONNECT packet and is inserted into the regex pattern without escaping special regex characters. This flaw enables an authenticated MQTT user to inject regex operators to bypass authorization.

CVE-2026-44838 (medium)

https://nvd.nist.gov/vuln/detail/CVE-2026-44838