Resource exhaustion in nats-server - #VU135930
Published: June 30, 2026
Vulnerability identifier: #VU135930
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: N/A
CWE-ID: CWE-400
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 attacker to cause a denial of service.
The vulnerability exists due to uncontrolled resource consumption in the MQTT CONNECT packet parser when processing incomplete pre-authentication MQTT CONNECT packets. A remote attacker can send a large incomplete MQTT CONNECT packet to cause a denial of service.
Only servers with MQTT support enabled are affected.
Remediation
Install security update from vendor's website.