CVE-2026-44838
RabbitMQ MQTT Topic Permission Authorization Bypass
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 Vector Breakdown
AV:NAttack VectorAC:LAttack ComplexityPR:LPrivileges RequiredUI:NUser InteractionS:UScopeC:HConfidentialityI:HIntegrityA:NAvailabilityWeaknesses
Affected Products
Attack Graph
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Exploitability
MITRE ATT&CK
2 techniquesReferences
Timeline
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