Resource exhaustion in Linuxfoundation Nats-Server

CVE-2026-58210

NATS Server is a high-performance server for NATS.io, the cloud and edge native messaging system. Prior to 2.14.3 and 2.12.12, an unauthenticated MQTT client could cause the server to retain large incomplete MQTT CONNECT packets before authentication completed, consuming server memory while the parser waited for the advertised MQTT packet length. This issue is fixed in versions 2.14.3 and 2.12.12.

Vulnerability class: DoS (Denial of Service)

EPSS: 0.005 (41.2th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-58210?
CVE-2026-58210 is a high-severity vulnerability in Linuxfoundation Nats-Server, classified under Uncontrolled Resource Consumption. CVSS score: 7.5/10. Published 2026-07-08.
How severe is CVE-2026-58210?
High severity. CVSS v3 base score is 7.5 out of 10.