CVE-2026-58208

EUVD-2026-42391
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.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
NISTPrimary
6.8 MEDIUM
NETWORK
HIGH
NONE
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:H
Base Score
CVSS 3.x
EPSS Score
Percentile: 26.79%
Affected Products (NVD)
VendorProductVersion
linuxfoundationnats-server
2.12.0 ≤
𝑥
< 2.12.12
linuxfoundationnats-server
2.14.0 ≤
𝑥
< 2.14.3
𝑥
= Vulnerable software versions
Debian logo
Debian Releases
Debian Product
Codename
nats-server
bookworm
vulnerable
forky
2.14.3-1
fixed
sid
2.14.3-1
fixed
trixie
vulnerable
Ubuntu logo
Ubuntu Releases
Ubuntu Product
Codename
nats-server
jammy
dne
noble
needs-triage
questing
ignored
resolute
needs-triage
Azure Linux logo
Azure Linux Releases
Azure Package
Release
telegraf
Azure Linux 3.0
0:1.31.0-24.azl3
fixed
Common Weakness Enumeration
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