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OpenAdvisories
Medium · 4.3 CVE-2026-58209 EUVD-2026-42347

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

Published Jul 8, 2026 · Updated Jul 9, 2026 · Assigned by GitHub_M

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.

Affected products

VendorProductAffectedFixed
nats-io nats-server < 2.12.12, >= 2.14.0-RC.1, < 2.14.3 —

Fixed in Linux distributions

Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.

ReleasePackageFixed inAdvisory
Debian 14 nats-server 2.14.3-1 —
Debian 13 nats-server No fix yet —
Debian 12 nats-server No fix yet —
ReleasePackageFixed inAdvisory
Ubuntu 26.10 nats-server No fix yet —
Ubuntu 25.10 nats-server No fix yet —
Ubuntu 24.04 LTS nats-server No fix yet —
Show 1 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
Ubuntu Pro 26.04 LTS nats-server No fix yet —
ReleasePackageFixed inAdvisory
Red Hat Hardened Images 1 nats-server2.12 2.12.12-1.hum1 RHSA-2026:36017
Red Hat Hardened Images 1 nats-server2.14 2.14.3-1.hum1 RHSA-2026:36016

Azure Linux

ReleasePackageFixed inAdvisory
Azure Linux 3 telegraf 1.31.0-27 —

Advisories 3

References