CVE-2026-58213
NATS Server: MQTT SUBSCRIBE Protocol Injection via Leaf Node/Route Forwarding allows arbitrary NATS command injection
7.1
HIGH
CVSS 3.1
EPSS 0.44%
Description
NATS Server is a high-performance server for NATS.io, the cloud and edge native messaging system. Prior to 2.14.1 and 2.12.9, an MQTT client could include protocol control characters in subscription filters that were later forwarded as NATS protocol data to route or leafnode connections, corrupting the forwarded protocol stream and allowing injection of unintended NATS protocol operations. This issue is fixed in versions 2.14.1 and 2.12.9.
How to fix CVE-2026-58213
To remediate CVE-2026-58213, upgrade the affected package to a fixed version below.
- —upgrade to 2.12.9 or later
Is CVE-2026-58213 being exploited?
Low — EPSS is 0.4%, meaning exploitation activity has not been observed at scale.
Affected packages (1)
- from 0, < 2.12.9, >= 2.14.0, < 2.14.1
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | HIGH7.1 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N |