CVE-2026-58209

MEDIUM

NATS Server: MQTT retained and QoS replay bypass subscribe deny filters

Title source: cna
STIX 2.1

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.

References (5)

Core 5

Scores

CVSS v3 4.3
EPSS 0.0034
EPSS Percentile 26.3%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

CISA SSVC

Vulnrichment
Exploitation none
Automatable no
Technical Impact partial

Details

CWE
CWE-863
Status published
Products (3)
linuxfoundation/nats-server < 2.12.12
nats-io/nats-server < 2.12.12
nats-io/nats-server >= 2.14.0-RC.1, < 2.14.3
Published Jul 08, 2026
Tracked Since Jul 09, 2026