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.
SeverityHigh
CVSS8.8
Exploit probability—
ProductLinuxfoundation Nats-server
PublishedJul 8, 2026
First seenJul 8, 2026
Weakness typeCWE-287Improper authentication
How to fix
Update
- linuxfoundation nats-server2.11.16, 2.12.7 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| linuxfoundation nats-server | v < 2.11.16, 2.12.0 ≤ v < 2.12.7 | 2.11.16, 2.12.7 |
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