Improper Authentication Affecting github.com/nats-io/nats-server/v2/server package, versions <2.11.16>=2.12.0-preview.1 <2.12.6>=2.14.0-RC.1 <2.14.0
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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- published9 Jul 2026
- disclosed8 Jul 2026
- creditXlabAI Team, Keenan
Introduced: 8 Jul 2026
CVE-2026-58253 Â (opens in a new tab)How to fix?
Upgrade github.com/nats-io/nats-server/v2/server to version 2.11.16, 2.12.6, 2.14.0 or higher.
Overview
github.com/nats-io/nats-server/v2/server is an A simple, secure and performant communications system for digital systems, services and devices.
Affected versions of this package are vulnerable to Improper Authentication in the parser fast path for inter-server connections, which applies a fast path intended for ordinary client connections to route and leafnode connection types when no_auth_user is enabled. An attacker with network access to a route or leafnode listener can bypass inter-server authentication and obtain the privileges of that connection type by connecting as an unauthenticated peer before the CONNECT authentication flow completes. Exploitation requires no_auth_user to be configured together with route or leafnode listeners.