CVE-2026-58211 — MEDIUM (5.4)

Q: How severe is CVE-2026-58211?

CVE-2026-58211 has been rated MEDIUM with a CVSS base score of 5.4/10. Review the CVSS metrics above for detailed severity breakdown.

Q: Is there a patch for CVE-2026-58211?

Check the references section above for vendor advisories and patch information. Affected products include: Linuxfoundation Nats-Server.

Vulnerability Description

NATS Server is a high-performance server for NATS.io, the cloud and edge native messaging system. Prior to 2.14.3 and 2.12.12, a client could be registered as the configured no_auth_user through a parser path used when the first client operation was not CONNECT, bypassing user-level connection restrictions such as allowed_connection_types or proxy_required that normal authentication would apply. This issue is fixed in versions 2.14.3 and 2.12.12.

CVSS Score

5.4

MEDIUM

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

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

NONE

Scope

UNCHANGED

Confidentiality

LOW

Integrity

LOW

Availability

NONE

Affected Products

Vendor	Product	Versions
Linuxfoundation	Nats-Server	>= 2.12.0, < 2.12.12

Related Weaknesses (CWE)

CWE-863

References

https://github.com/nats-io/nats-server/security/advisories/GHSA-hmmp-q8cx-v964MitigationVendor Advisory

FAQ

What is CVE-2026-58211?

CVE-2026-58211 is a vulnerability with a CVSS score of 5.4 (MEDIUM). NATS Server is a high-performance server for NATS.io, the cloud and edge native messaging system. Prior to 2.14.3 and 2.12.12, a client could be registered as the configured no_auth_user through a par...

How severe is CVE-2026-58211?

CVE-2026-58211 has been rated MEDIUM with a CVSS base score of 5.4/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-58211?

Check the references section above for vendor advisories and patch information. Affected products include: Linuxfoundation Nats-Server.