CVE-2026-58253
Published:July 08, 2026
Updated:August 04, 2026
NATS Server is a high-performance server for NATS.io, the cloud and edge native messaging system. Prior to 2.14.0, 2.12.7, and 2.11.16, when no_auth_user was configured, a parser fast path intended for ordinary client connections could also apply to route or leafnode listeners, allowing an unauthenticated peer to bypass inter-server CONNECT authentication and operate with the privileges associated with that connection type. This issue is fixed in versions 2.14.0, 2.12.7, and 2.11.16.
Affected Packages
https://github.com/nats-io/nats-server.git (GITHUB):
Affected version(s) >=v2.12.0 <v2.12.7Fix Suggestion:
Update to version v2.12.7https://github.com/nats-io/nats-server.git (GITHUB):
Affected version(s) >=v0.5.1 <v2.11.16Fix Suggestion:
Update to version v2.11.16github.com/nats-io/nats-server/v2 (GO):
Affected version(s) >=v2.12.0 <v2.12.7Fix Suggestion:
Update to version v2.12.7github.com/nats-io/nats-server/v2 (GO):
Affected version(s) >=v2.0.0-RC14.0.20190604014547-ed1901c79292 <v2.11.16Fix Suggestion:
Update to version v2.11.16Related Resources (9)
Do you need more information?
Contact UsCVSS v4
Base Score:
8.5
Attack Vector
ADJACENT
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
LOW
Vulnerable System Integrity
HIGH
Vulnerable System Availability
LOW
Subsequent System Confidentiality
LOW
Subsequent System Integrity
HIGH
Subsequent System Availability
LOW
CVSS v3
Base Score:
8.8
Attack Vector
ADJACENT
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
CHANGED
Confidentiality
LOW
Integrity
HIGH
Availability
LOW
Weakness Type (CWE)
Improper Authentication
EPSS
Base Score:
0.23