Improper Validation of Syntactic Correctness of Input in RabbitMQ Server - CVE-2026-44838
Published: May 6, 2026
Vulnerability identifier: #VU130271
CSH Severity: Low
CVSS v4: 5.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-44838
CWE-ID: CWE-1286
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to bypass topic authorization and access restricted topics.
The vulnerability exists due to improper neutralization of special elements in the MQTT topic permission authorization logic when substituting user-supplied client_id values into regular expression patterns. A remote user can supply a crafted client_id containing regex metacharacters to bypass topic authorization and access restricted topics.
This issue affects deployments that use variable substitution such as {client_id} in MQTT topic authorization patterns.
Affected software
RabbitMQ Server
How to mitigate CVE-2026-44838
Install security update from vendor's website.
RabbitMQ Server - update to 4.2.4