Incorrect Authorization Affecting github.com/nats-io/nats-server/v2/server package, versions <2.12.12>=2.14.0-RC.1 <2.14.3
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.
Do your applications use this vulnerable package?
In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.
Test your applicationsSnyk Learn
Learn about Incorrect Authorization vulnerabilities in an interactive lesson.
Start learning- Snyk IDSNYK-GOLANG-GITHUBCOMNATSIONATSSERVERV2SERVER-17900565
- published9 Jul 2026
- disclosed8 Jul 2026
- creditAsritha Bodepudi
Introduced: 8 Jul 2026
CVE-2026-58211 Â (opens in a new tab)How to fix?
Upgrade github.com/nats-io/nats-server/v2/server to version 2.12.12, 2.14.3 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 Incorrect Authorization in the parser path for non-CONNECT initial client operations, which registers a client as the configured no_auth_user without applying the user-level connection restrictions enforced on the normal authentication path. An attacker can bypass the allowed_connection_types or proxy_required limits placed on the no_auth_user by making the first operation something other than CONNECT, which routes the connection through that fast path. Exploitation applies only to deployments that configure no_auth_user, and the impact is bounded by the permissions granted to that default user.
Workaround
This vulnerability can be avoided by not relying on allowed_connection_types or proxy_required as the only boundary for the no_auth_user, enforcing the intended restrictions through additional controls as well.