{"id":"CVE-2026-58211","summary":"NATS Server: `no_auth_user` pre-CONNECT fast path bypasses user connection restrictions","details":"NATS Server is a high-performance server for NATS.io, the cloud and edge native messaging system. Prior to 2.14.3 and 2.12.12, a client could be registered as the configured no_auth_user through a parser path used when the first client operation was not CONNECT, bypassing user-level connection restrictions such as allowed_connection_types or proxy_required that normal authentication would apply. This issue is fixed in versions 2.14.3 and 2.12.12.","aliases":["GHSA-hmmp-q8cx-v964"],"modified":"2026-08-12T03:51:28.386378529Z","published":"2026-07-08T20:16:25.262Z","database_specific":{"cwe_ids":["CWE-863"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/58xxx/CVE-2026-58211.json","cna_assigner":"GitHub_M"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/58xxx/CVE-2026-58211.json"},{"type":"ADVISORY","url":"https://github.com/nats-io/nats-server/security/advisories/GHSA-hmmp-q8cx-v964"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-58211"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/nats-io/nats-server","events":[{"introduced":"fc6ec648d806652d282d2f0edb6cb9f22c895572"},{"fixed":"e8de2a67c7a094abca6013931ecf6cbff4b3fb02"},{"introduced":"0cbd01caf8f29011c26273ff7662addd3830396a"},{"fixed":"9b17a586be69c9ff36e4c84a421ca47da410b561"}],"database_specific":{"cpe":"cpe:2.3:a:linuxfoundation:nats-server:*:*:*:*:*:*:*:*","extracted_events":[{"introduced":"2.12.0"},{"fixed":"2.12.12"},{"introduced":"2.14.0"},{"fixed":"2.14.3"}],"source":"CPE_RANGE"}}],"versions":["v2.14.2","v2.12.11","v2.12.10","v2.12.10-RC.1","v2.14.2-RC.1","v2.14.1","v2.12.9","v2.14.1-RC.2","v2.12.9-RC.2","v2.14.1-RC.1","v2.12.9-RC.1","v2.12.8","v2.14.0","v2.12.7","v2.12.4","v2.12.6","v2.12.5","v2.12.5-RC.2","v2.12.5-RC.1","v2.12.4-RC.6","v2.12.4-RC.5","v2.12.4-RC.4","v2.12.2","v2.12.4-RC.3","v2.12.4-RC.2","v2.12.4-RC.1","v2.12.3","v2.12.3-RC.5","v2.12.3-RC.4","v2.12.3-RC.3","v2.12.3-RC.2","v2.12.3-RC.1","v2.12.2-RC.4","v2.12.2-RC.3","v2.12.1","v2.12.2-RC.2","v2.12.2-RC.1","v2.12.0","v2.12.1-RC.5","v2.12.1-RC.4","v2.12.1-RC.3","v2.12.1-RC.2","v2.12.1-RC.1"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-58211.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N"}]}