CVE-2026-33249
Medium
Description
NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Starting in version 2.11.0 and prior to versions 2.11.15 and 2.12.6, a valid client which uses message tracing headers can indicate that the trace messages can be sent to an arbitrary valid subject, including those to which the client does not have publish permission. The payload is a valid trace message and not chosen by the attacker. Versions 2.11.15 and 2.12.6 contain a fix. No known workarounds are available.
SeverityMedium
CVSS4.3
Exploit probability—
ProductLinuxfoundation Nats-server
PublishedMar 25, 2026
First seenMar 25, 2026
Weakness typeCWE-863Incorrect authorization
How to fix
Update
- linuxfoundation nats-server2.11.15, 2.12.6 or later
- github.com/nats-io/nats-server/v22.11.15, 2.12.6 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| linuxfoundation nats-server | 2.11.0 ≤ v < 2.11.15, 2.12.0 ≤ v < 2.12.6 | 2.11.15, 2.12.6 |
| github.com/nats-io/nats-server/v2Go | 2.11.0 ≤ v < 2.11.15, 2.12.0-preview.1 ≤ v < 2.12.6 | 2.11.15, 2.12.6 |
| github.com/nats-io/nats-serverGo | No range specified | — |
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