CVE-2026-58209
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, 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.
SeverityMedium
CVSS4.3
Exploit probability—
ProductLinuxfoundation Nats-server
PublishedJul 8, 2026
First seenJul 8, 2026
Weakness typeCWE-863Incorrect authorization
How to fix
Update
- linuxfoundation nats-server2.12.12, 2.14.3 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| linuxfoundation nats-server | v < 2.12.12, 2.14.0 ≤ v < 2.14.3 | 2.12.12, 2.14.3 |
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