CVE-2026-44838
MEDIUM EPSS 16.2%
Published May 27, 20261mo ago · Modified Jun 17, 20261w ago
5.3 CVSS 4.0
Published May 27, 2026 1mo ago
Last Modified Jun 17, 2026 1w ago
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 Details
Base Score
Exploitability
Impact
Vector string
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:L/SC:H/SI:H/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Attack Vector Network
Attack Complexity Low
Privileges Required Low
User Interaction None
Scope X
Threat Intelligence
EPSS Exploit Probability
16.2% percentile
Exploit & Patch Status
No Known Exploit
No Patch Available
Weaknesses 1
CWE-863 Incorrect Authorization Authorization
Affected Products 1
| Vendor | Product | Version | Range |
|---|---|---|---|
| broadcom | rabbitmq_server | * | ≥4.2.0 – <4.2.4 |
References 1
- github.com https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-x866-xp2g-cx8v
Remediation
No remediation data recorded yet
Check vendor advisories and the NVD entry for patch availability.