CVE-2026-44838
CWE-863Published: May 27, 2026· Updated: May 29, 2026
Official 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.
Technical Analysis
CVE-2026-44838 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.
Exploitation requires low privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
CVSS v3.1 Vector Breakdown
Exploit & PoC Resources
All References (1)
Quick Facts
Related CVEs (CWE-863)
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2026-44838 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts