CVE-2026-33223
NATS Server: Incomplete Stripping of Nats-Request-Info Header Allows Identity Spoofing
Description
NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Prior to versions 2.11.15 and 2.12.6, the NATS message header `Nats-Request-Info:` is supposed to be a guarantee of identity by the NATS server, but the stripping of this header from inbound messages was not fully effective. An attacker with valid credentials for any regular client interface could thus spoof their identity to services which rely upon this header. Versions 2.11.15 and 2.12.6 contain a fix. No known workarounds are available.
How to fix CVE-2026-33223
To remediate CVE-2026-33223, upgrade the affected package to a fixed version below.
- —upgrade to 2.11.15 or later
- —no fix listed
- —no fix listed
- —no fix listed
- —upgrade to 2.11.15 or later
- —upgrade to 2.11.15 or later
Is CVE-2026-33223 being exploited?
Low — EPSS is 0.0%, meaning exploitation activity has not been observed at scale.
Affected packages (6)
- from 0, < 2.11.15, >= 2.12.0, < 2.12.6
- from 0
- from 0
- from 0
- from 0, < 2.11.15
- from 0, < 2.11.15, >= 2.12.0-RC.1, < 2.12.6
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | MEDIUM6.4 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N |