Resource exhaustion in nats-server - CVE-2026-58210
Published: June 30, 2026
Vulnerability identifier: #VU135930
CSH Severity: Medium
CVSS v4: 8.7 [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]
CVE-ID: CVE-2026-58210
CWE-ID: CWE-400
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
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.
Affected software
nats-server
How to mitigate CVE-2026-58210
Install security update from vendor's website.
nats-server - addressed in versions 2.12.12, 2.14.3