CVE-2026-58253

high

Description

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.

References

https://github.com/nats-io/nats-server/security/advisories/GHSA-38x3-76xf-cq45

https://github.com/nats-io/nats-server/releases/tag/v2.14.0

https://github.com/nats-io/nats-server/releases/tag/v2.12.7

https://github.com/nats-io/nats-server/releases/tag/v2.11.16

https://github.com/nats-io/nats-server/commit/b86147e81710a52b72a7f7275f91d69f723f5cb3

https://github.com/nats-io/nats-server/commit/8b8e1ad4ceed32321e00d4fc6e76be05bc13bca6

https://github.com/nats-io/nats-server/commit/7b81dd455ea95960090a84858c7662827948d1b6

Details

Source: Mitre, NVD

Published: 2026-07-08

Updated: 2026-07-13

Risk Information

CVSS v2

Base Score: 7.3

Vector: CVSS2#AV:A/AC:L/Au:N/C:P/I:C/A:P

Severity: High

CVSS v3

Base Score: 8.8

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

Severity: High

EPSS

EPSS: 0.00388