CVE-2026-58208 | NATS Server is a high-performance server for NATS.io, the cl… | CVSS 6.8 MEDIUM

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, 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.

Metadata

CVE ID: CVE-2026-58208
State: PUBLISHED
Assigner: GitHub_M
Reserved: 2026-06-29 17:09 UTC
Published: 2026-07-08 20:17 UTC
Last updated: 2026-07-08 20:17 UTC
Primary CWE: CWE-248
CWE-248: Uncaught Exception
Vendor / Product: nats-io / nats-server
Sources: cve.org · NVD

Severity & Metrics

6.8 MEDIUM CVSS 3.1

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:H

Affected products (1)

Vendor	Product	Platform	Versions
nats-io	nats-server	—	>= 2.14.0-RC.1, < 2.14.3, < 2.12.12

Weakness (CWE)

CWE	Source	Description
CWE-248	cna	CWE-248: Uncaught Exception

CVSS scores (1)

Score	Severity	Version	Source	Vector
6.8	MEDIUM	3.1	cna	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:H

References (5)

https://github.com/nats-io/nats-server/security/advisories/GHSA-p957-7v2w-g93g https://github.com/nats-io/nats-server/security/advisories/GHSA-p957-7v2w-g93g
https://github.com/nats-io/nats-server/commit/73b3dd9a5ea0fa7bf08b702338676355b29b5fb4 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/commit/837536b98b3a9280b993282155ff2bdd3ca38c30
https://github.com/nats-io/nats-server/releases/tag/v2.12.12 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/releases/tag/v2.14.3