CVE-2026-58209

Severity CVSS v4.0:

Pending analysis

Type:

Unavailable / Other

Publication date:

08/07/2026

Last modified:

13/07/2026

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, MQTT retained message delivery and QoS1+ durable replay could deliver messages whose original topics matched a subscriber configured subscribe deny rule because these delivery paths did not consistently recheck the concrete original topic before sending the MQTT PUBLISH to the subscriber. This issue is fixed in versions 2.14.3 and 2.12.12.

Impact

Vector 3.x

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N CVSS v3.1 Severity and Metrics:

Base Score: 4.30 MEDIUM
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): Low
User Interaction (UI): None
Scope (S): Unchanged
Confidentiality (C): Low
Integrity (I): None
Availability (A): None

Base Score 3.x

4.30

Severity 3.x

MEDIUM

Vulnerable products and versions

CPE	From	Up to
cpe:2.3:a:linuxfoundation:nats-server::::::::		2.12.12 (excluding)
cpe:2.3:a:linuxfoundation:nats-server::::::::	2.14.0 (including)	2.14.3 (excluding)

To consult the complete list of CPE names with products and versions, see this page

CVE-2026-58209

Description

Impact

Vulnerable products and versions

References to Advisories, Solutions, and Tools