CVE-2026-33249
NATS: Message tracing can be redirected to arbitrary subject
4.3
MEDIUM
CVSS 3.1
EPSS 0.01%
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.
How to fix CVE-2026-33249
To remediate CVE-2026-33249, upgrade the affected package to a fixed version below.
- —upgrade to 2.11.15 or later
- —upgrade to 2.12.6-1 or later
- —no fix listed
- —upgrade to 2.11.15 or later
- —upgrade to 2.11.15 or later
Is CVE-2026-33249 being exploited?
Low — EPSS is 0.0%, meaning exploitation activity has not been observed at scale.
Affected packages (5)
- >= 2.11.0, < 2.11.15, >= 2.12.0, < 2.12.6
- from 0, < 2.12.6-1
- from 0
- >= 2.11.0, < 2.11.15
- >= 2.11.0, < 2.11.15, >= 2.12.0-preview.1, < 2.12.6
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | MEDIUM4.3 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N |