CVE-2026-58210
NATS Server: MQTT partial CONNECT packets can exhaust pre-auth memory
7.5
HIGH
CVSS 3.1
EPSS 0.73%
Description
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.
How to fix CVE-2026-58210
To remediate CVE-2026-58210, upgrade the affected package to a fixed version below.
- —upgrade to 2.12.12 or later
Is CVE-2026-58210 being exploited?
Low — EPSS is 0.7%, meaning exploitation activity has not been observed at scale.
Affected packages (1)
- from 0, < 2.12.12, >= 2.14.0, < 2.14.3
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | HIGH7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |