Threats Tagged 'cve-2026-44838'

RabbitMQ is a messaging and streaming broker. From 4.2.0 to before 4.2.4, RabbitMQ's MQTT plugin allows for topic-level authorization using regular expressions with variable substitution. Administrators can create patterns such as ^{client_id}-sensors$ to restrict user access to topics that include their client ID. However, the client_id 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. This vulnerability is fixed in 4.2.4 and 4.3.0.

CVE-2026-44838 is a medium severity vulnerability in RabbitMQ's MQTT plugin versions 4.2.0 up to but not including 4.2.4. It involves incorrect authorization due to improper handling of user-supplied client_id values in topic-level authorization regex patterns. Because the client_id is inserted into regex patterns without escaping special characters, an authenticated MQTT user can inject regex operators to bypass topic access restrictions. This flaw is fixed in RabbitMQ versions 4.2.4 and 4.