CVE-2026-33218

EUVD-2026-15968

25.03.2026, 20:16

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, a client which can connect to the leafnode port can crash the nats-server with a certain malformed message pre-authentication. Versions 2.11.15 and 2.12.6 contain a fix. As a workaround, disable leafnode support if not needed or restrict network connections to the leafnode port, if plausible without compromising the service offered.

Provider	Type	Base Score	Atk. Vector	Atk. Complexity	Priv. Required	Vector
NIST	Primary	7.5 HIGH	NETWORK	LOW	NONE	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
GitHub_M	CNA	7.5 HIGH	NETWORK	LOW	NONE	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Base Score

CVSS 3.x

EPSS Score

Percentile: Unknown

Affected Products (NVD)

Vendor	Product	Version
linuxfoundation	nats-server	𝑥 < 2.11.15
linuxfoundation	nats-server	2.12.0 ≤ 𝑥 < 2.12.6

𝑥

= Vulnerable software versions

Common Weakness Enumeration

CWE-20 - Improper Input Validation
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.

References

https://advisories.nats.io/CVE/secnote-2026-10.txt

https://github.com/nats-io/nats-server/security/advisories/GHSA-vprv-35vv-q339