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CVE-2026-44838

5.3 medium SSVC exploitation: none Analyzed

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.

Fix

Patch, vendor advisory and mitigation references on NVD 1

Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.

Change history 1

  1. First seenCVSS 5.3 · broadcomNVD modified 2026-10-26 11:10

Affected (CPE criteria) 1

  • cpe:2.3:a:broadcom:rabbitmq_server:*:*:*:*:*:*:*:*

References 1