Vulnerability Description
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.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Broadcom | Rabbitmq Server | >= 4.2.0, < 4.2.4 |
Related Weaknesses (CWE)
References
FAQ
What is CVE-2026-44838?
CVE-2026-44838 is a vulnerability with a CVSS score of 8.1 (HIGH). 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. Administrato...
How severe is CVE-2026-44838?
CVE-2026-44838 has been rated HIGH with a CVSS base score of 8.1/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-44838?
Check the references section above for vendor advisories and patch information. Affected products include: Broadcom Rabbitmq Server.