Incorrect authorization in nats-server - #VU135934
Published: June 30, 2026
Vulnerability identifier: #VU135934
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: N/A
CWE-ID: CWE-863
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: NATS - The Cloud Native Messaging System
Affected software:
nats-server
nats-server
Detailed vulnerability description
The vulnerability allows a remote user to disclose sensitive information.
The vulnerability exists due to improper access control in internal $MQTT.deliver.pubrel subjects when processing MQTT subscribe requests. A remote user can subscribe to an internal MQTT delivery subject to disclose sensitive information.
Only MQTT QoS2 protocol metadata for sessions in the account is exposed; message payloads are not exposed through this path.
Remediation
Install security update from vendor's website.