CVE-2026-33249 MEDIUM

CVE-2026-33249: NATS: Message tracing can be redirected to arbitrary subject

Vendor Nats-Io
Product nats-server
Weakness CWE-863 · Incorrect authorization
Published March 25, 2026
Last update March 26, 2026

CVSS base score

4.3/10
Attack vector Network
Attack complexity Low
Privileges required Low
User interaction None
Confidentiality None
Integrity Low

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

March 25, 2026 CVE published
March 26, 2026 Record updated