CVE-2026-33249

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.

Score

CVSS 3.1 4.3 Medium

Status

Analyzed - security-advisories@github.com

Published

2026-03-25

Last modified

2026-03-26

Weaknesses

CWE-863

Affected products

• Nats-server (Linuxfoundation)
• Nats-server (Nats-io)

References

• https://advisories.nats.io/CVE/secnote-2026-15.txt
• https://github.com/nats-io/nats-server/security/advisories/GHSA-8m2x-3m6q-6w8j