CVE-2026-58209 — NATS Server: MQTT retained and QoS replay bypass subscribe deny filters
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 r…
Published: 2026-07-08 · CVSS: 4.3 · CVSS 3.1
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.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7