CVE-2026-44838
highpriority · track · 32OT risk · elevatedEPSS 0.002 · 10 %ileDEEUUSEPSS · scored 2026-10-23
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
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · low–high · 1.3–8.1
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (11)
Products and version ranges known to be affected.
advisories (2)
Vendor and ecosystem advisories describing this.
- WID-SEC-W-2026-1397RabbitMQ: Mehrere SchwachstellenDeutsch2026-05-06csaf · cert_bundDE
Ein Angreifer kann mehrere Schwachstellen in RabbitMQ ausnutzen, um einen Cross-Site Scripting Angriff durchzuführen, und um Sicherheitsvorkehrungen zu umgehen.
- BIT-rabbitmq-2026-44838RabbitMQ MQTT Topic Permission Authorization Bypass2026-05-29vendor · osvUS
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.
also known as (3)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (4)
External citations — patches, advisories, analysis.
- https://github.com/rabbitmq/rabbitmq-server/releasesPatchcnnvd
- https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-x866-xp2g-cx8vcnnvd
- https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-x866-xp2g-cx8venisa_euvd
- https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-x866-xp2g-cx8vVendor Advisorynvd
Attackers weaponise vulnerabilities like this against internet-exposed services. See what is exposed on your perimeter with a free passive scan.
Free scan