CVE-2026-33246 — Improper Authentication in Nats-server

CWE-287 — Improper AuthenticationCWE-290 — Authentication Bypass by Spoofing9 documents6 sources
Severity
5.4MEDIUMNVD
EPSS
0.0%
top 92.96%
CISA KEV
Not in KEV
Exploit
No known exploits
Affected products
4
Nats-io Nats-serverLinuxfoundation Nats-serverGithub.com Nats-io Nats-server V2+1 more
Timeline
PublishedMar 25
Latest updateMar 26

Description

NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. The nats-server offers a `Nats-Request-Info:` message header, providing information about a request. This is supposed to provide enough information to allow for account/user identification, such that NATS clients could make their own decisions on how to trust a message, provided that they trust the nats-server as a broker. A leafnode connecting to a nats-server is not fully trusted unless the system a…

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:NExploitability: 2.8 | Impact: 2.5

Affected Packages5 packages

▶debiandebian/nats-server< nats-server 2.12.6-1 (forky)
▶CVEListV5nats-io/nats-server< 2.11.15+1
▶NVDlinuxfoundation/nats-server2.12.0 — 2.12.6+1
▶Gogithub.com/nats-io_nats-server_v22.12.0-RC.1 — 2.12.6+1
▶Debianlinuxfoundation/nats-server< 2.12.6-1

🔴Vulnerability Details

4
OSV
NATS: Leafnode connections allow spoofing of Nats-Request-Info identity headers in github.com/nats-io/nats-server↗2026-03-26
▶
OSV
CVE-2026-33246: NATS-Server is a High-Performance server for NATS↗2026-03-25
▶
GHSA
NATS: Leafnode connections allow spoofing of Nats-Request-Info identity headers↗2026-03-24
▶
OSV
NATS: Leafnode connections allow spoofing of Nats-Request-Info identity headers↗2026-03-24
▶

📋Vendor Advisories

2
Red Hat
nats-server: nats: github.com/nats-io/nats-server: NATS-Server: Client identity spoofing via Nats-Request-Info header manipulation↗2026-03-25
▶
Debian
CVE-2026-33246: nats-server - NATS-Server is a High-Performance server for NATS.io, a cloud and edge native me...↗2026
▶

🕵️Threat Intelligence

1
Wiz
CVE-2026-33246 Impact, Exploitability, and Mitigation Steps | Wiz↗
▶