CVE-2026-44838: RabbitMQ MQTT Topic Permission Authorization Bypass
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 ^{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. This vulnerability is fixed in 4.2.4 and 4.3.0.
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2026-44838?
The severity of CVE-2026-44838 is medium with a score of 5.3.
How do I fix CVE-2026-44838?
To fix CVE-2026-44838, upgrade RabbitMQ to version 4.2.4 or later.
What kind of vulnerability is CVE-2026-44838?
CVE-2026-44838 is a permission authorization bypass vulnerability in RabbitMQ's MQTT plugin.
Which versions of RabbitMQ are affected by CVE-2026-44838?
CVE-2026-44838 affects RabbitMQ versions from 4.2.0 to before 4.2.4.
What impact does CVE-2026-44838 have on RabbitMQ users?
CVE-2026-44838 allows unauthorized access to MQTT topics, potentially compromising message security.