{"id":"CVE-2026-58211","aliases":["DEBIAN-CVE-2026-58211","EUVD-2026-42390","GHSA-hmmp-q8cx-v964","RHSA-2026:36016","RHSA-2026:36017","UBUNTU-CVE-2026-58211"],"status":"published","title":"NATS Server: `no_auth_user` pre-CONNECT fast path bypasses user connection restrictions","description":"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.","severity":{"version":"3.1","score":5.4,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-09","score":0.00292,"percentile":0.21958,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-863"],"published":"2026-07-08T20:16:25Z","modified":"2026-10-28T02:30:50Z","fixes":[{"ecosystem":"Debian:14","package":"nats-server","fixed_in":["2.14.3-1"],"sources":["osv"]}],"affected":[{"source":"osv","ecosystem":"Debian:12","package":"nats-server","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.10.1-1","2.10.16-1","2.10.18-1","2.10.24-1","2.10.27-1","2.10.3-1","2.10.4-1","2.10.7-1","2.12.4-1","2.12.6-1","2.14.1-1","2.14.3-1","2.14.6-1","2.15.1-1","2.9.10-1","2.9.19-1"]},{"source":"osv","ecosystem":"Debian:13","package":"nats-server","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.10.27-1","2.12.4-1","2.12.6-1","2.14.1-1","2.14.3-1","2.14.6-1","2.15.1-1"]},{"source":"osv","ecosystem":"Debian:14","package":"nats-server","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.14.3-1"}]}],"versions":["2.10.27-1","2.12.4-1","2.12.6-1","2.14.1-1"]},{"source":"osv","ecosystem":"Red Hat:hummingbird:1","package":"nats-server2.14","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0:2.14.3-1.hum1"}]}],"bundled":6},{"source":"osv","ecosystem":"Red Hat:hummingbird:1","package":"nats-server2.12","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0:2.12.12-1.hum1"}]}],"bundled":6},{"source":"osv","ecosystem":"Ubuntu:24.04:LTS","package":"nats-server","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.9.19-1build1","2.10.3-1","2.10.4-1","2.10.7-1","2.10.7-1ubuntu0.1","2.10.7-1ubuntu0.2","2.10.7-1ubuntu0.3"]},{"source":"osv","ecosystem":"Ubuntu:25.10","package":"nats-server","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.10.24-1","2.10.27-1"]},{"source":"osv","ecosystem":"Ubuntu:26.10","package":"nats-server","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.10.27-1build1","2.14.1-1","2.14.3-1"]},{"source":"osv","ecosystem":"Ubuntu:Pro:26.04:LTS","package":"nats-server","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.10.27-1","2.10.27-1build1","2.10.27-1ubuntu0.26.04.1~esm1"]}],"products":[{"vendor":"linuxfoundation","product":"nats-server"},{"vendor":"nats-io","product":"nats-server"}],"references":[{"url":"https://github.com/nats-io/nats-server/security/advisories/GHSA-hmmp-q8cx-v964","tags":["x_refsource_CONFIRM","Mitigation","Vendor Advisory","advisory","article","report"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/58xxx/CVE-2026-58211.json","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-58211","tags":["advisory"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2026-58211","tags":["advisory"]},{"url":"https://access.redhat.com/errata/RHSA-2026:36016","tags":["advisory"]},{"url":"https://images.redhat.com/","tags":["article"]},{"url":"https://access.redhat.com/security/cve/CVE-2026-58213","tags":["report"]},{"url":"https://access.redhat.com/security/updates/classification/","tags":["article"]},{"url":"https://access.redhat.com/security/cve/CVE-2026-58210","tags":["report"]},{"url":"https://access.redhat.com/security/cve/CVE-2026-58211","tags":["report"]},{"url":"https://access.redhat.com/security/cve/CVE-2026-58209","tags":["report"]},{"url":"https://access.redhat.com/security/cve/CVE-2026-58214","tags":["report"]},{"url":"https://access.redhat.com/security/cve/CVE-2026-58254","tags":["report"]},{"url":"https://security.access.redhat.com/data/csaf/v2/advisories/2026/rhsa-2026_36016.json","tags":["advisory"]},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2498259","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-58209","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-58209","tags":["advisory"]},{"url":"https://github.com/nats-io/nats-server/commit/181b1f51f40b9954c57e9d478e051fb257679356","tags":["article"]},{"url":"https://github.com/nats-io/nats-server/commit/1c429b6fdc5afd4188cc5faf1127f6334896cd87","tags":["article"]},{"url":"https://github.com/nats-io/nats-server/releases/tag/v2.12.12","tags":["article"]},{"url":"https://github.com/nats-io/nats-server/releases/tag/v2.14.3","tags":["article"]},{"url":"https://github.com/nats-io/nats-server/security/advisories/GHSA-7qmq-8cc4-hxwg","tags":["article"]},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2498247","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-58210","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-58210","tags":["advisory"]},{"url":"https://github.com/nats-io/nats-server/commit/bce9ef39469e610aeddb819194ceb7f7edfc0861","tags":["article"]},{"url":"https://github.com/nats-io/nats-server/commit/e016e47bbf70304945f2ae9dc397e4862adefaf5","tags":["article"]},{"url":"https://github.com/nats-io/nats-server/security/advisories/GHSA-r72h-j7qq-v6qg","tags":["article"]},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2498258","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-58211","tags":["advisory","report"]},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2498249","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-58213","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-58213","tags":["advisory"]},{"url":"https://github.com/nats-io/nats-server/commit/366837cfc65ab9ccb4f98193c65e8daf238582d8","tags":["article"]},{"url":"https://github.com/nats-io/nats-server/commit/64ebae40051ee497c481e10f316238faf0de1736","tags":["article"]},{"url":"https://github.com/nats-io/nats-server/commit/f14856b9e57a36818f43851cb69b6e33670885c9","tags":["article"]},{"url":"https://github.com/nats-io/nats-server/pull/8163","tags":["article"]},{"url":"https://github.com/nats-io/nats-server/pull/8164","tags":["article"]},{"url":"https://github.com/nats-io/nats-server/releases/tag/v2.12.9","tags":["article"]},{"url":"https://github.com/nats-io/nats-server/releases/tag/v2.14.1","tags":["article"]},{"url":"https://github.com/nats-io/nats-server/security/advisories/GHSA-qrcv-3558-gj4f","tags":["article"]},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2498260","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-58214","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-58214","tags":["advisory"]},{"url":"https://github.com/nats-io/nats-server/commit/297b166be60fe13144084eed4b25201ead03204a","tags":["article"]},{"url":"https://github.com/nats-io/nats-server/commit/34b09657bb596d5f850eaa5cfc97ea6b2f989a97","tags":["article"]},{"url":"https://github.com/nats-io/nats-server/security/advisories/GHSA-4g68-3pwx-5vfj","tags":["article"]},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2498266","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-58254","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-58254","tags":["advisory"]},{"url":"https://github.com/nats-io/nats-server/commit/cbe845932980b71563efac5cfa4cc751c88936cd","tags":["article"]},{"url":"https://github.com/nats-io/nats-server/releases/tag/v2.12.8","tags":["article"]},{"url":"https://github.com/nats-io/nats-server/security/advisories/GHSA-p3j5-5hrq-p75h","tags":["article"]},{"url":"https://access.redhat.com/errata/RHSA-2026:36017","tags":["advisory"]},{"url":"https://security.access.redhat.com/data/csaf/v2/advisories/2026/rhsa-2026_36017.json","tags":["advisory"]},{"url":"https://ubuntu.com/security/CVE-2026-58211","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2026-58211","title":"NATS Server: `no_auth_user` pre-CONNECT fast path bypasses user connection restrictions","description":"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.","status":"published","published":"2026-07-08T20:16:25.262Z","modified":"2026-07-09T14:27:25.118Z","cvss":[{"version":"3.1","score":5.4,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N","level":"medium","assessor":"cna"}],"cwes":["CWE-863"],"updated_at":"2026-11-02T13:47:39.876248Z"}],"euvd":[{"id":"EUVD-2026-42390","description":"NATS Server is a high-performance server for NATS.io, the cloud and edge native messaging system. 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This issue is fixed in versions 2.14.3 and 2.12.12.","status":"published","published":"2026-07-08T21:16:52.61Z","modified":"2026-10-26T12:02:38.477629389Z","cvss":[{"version":"3.1","score":5.4,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N","level":"medium"}],"updated_at":"2026-11-02T15:45:57.590991Z"},{"id":"RHSA-2026:36016","title":"Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update","status":"published","published":"2026-08-22T10:22:44Z","modified":"2026-09-06T10:13:15Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"updated_at":"2026-11-02T15:53:19.963895Z"},{"id":"RHSA-2026:36017","title":"Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update","status":"published","published":"2026-08-22T10:22:45Z","modified":"2026-09-08T10:12:58Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"updated_at":"2026-11-02T15:53:19.963895Z"},{"id":"UBUNTU-CVE-2026-58211","description":"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.","status":"published","published":"2026-07-08T21:16:00Z","modified":"2026-10-17T12:59:13.538024814Z","cvss":[{"version":"3.1","score":5.4,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N","level":"medium"}],"updated_at":"2026-11-02T16:56:41.911783Z"}]}}