Vulnerability Details CVE-2026-58208
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, a WebSocket listener could route requests for the MQTT-over-WebSocket path into MQTT handling even when MQTT was not configured, allowing an unauthenticated client with access to the WebSocket listener to reach uninitialized MQTT state and crash the server process. This issue is fixed in versions 2.14.3 and 2.12.12.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.006
EPSS Ranking 44.2%
CVSS Severity
CVSS v3 Score 6.8
References
- https://github.com/nats-io/nats-server/commit/73b3dd9a5ea0fa7bf08b702338676355b29b5fb4
- https://github.com/nats-io/nats-server/commit/837536b98b3a9280b993282155ff2bdd3ca38c30
- https://github.com/nats-io/nats-server/releases/tag/v2.12.12
- https://github.com/nats-io/nats-server/releases/tag/v2.14.3
- https://github.com/nats-io/nats-server/security/advisories/GHSA-p957-7v2w-g93g
Products affected by CVE-2026-58208
-
cpe:2.3:a:linuxfoundation:nats-server:2.12.0
-
cpe:2.3:a:linuxfoundation:nats-server:2.12.1
-
cpe:2.3:a:linuxfoundation:nats-server:2.12.10
-
cpe:2.3:a:linuxfoundation:nats-server:2.12.11
-
cpe:2.3:a:linuxfoundation:nats-server:2.12.2
-
cpe:2.3:a:linuxfoundation:nats-server:2.12.3
-
cpe:2.3:a:linuxfoundation:nats-server:2.12.4
-
cpe:2.3:a:linuxfoundation:nats-server:2.12.5
-
cpe:2.3:a:linuxfoundation:nats-server:2.12.6
-
cpe:2.3:a:linuxfoundation:nats-server:2.12.7
-
cpe:2.3:a:linuxfoundation:nats-server:2.12.8
-
cpe:2.3:a:linuxfoundation:nats-server:2.12.9
-
cpe:2.3:a:linuxfoundation:nats-server:2.14.0
-
cpe:2.3:a:linuxfoundation:nats-server:2.14.1
-
cpe:2.3:a:linuxfoundation:nats-server:2.14.2