{"id":"CVE-2026-33216","aliases":["BIT-nats-2026-33216","GHSA-v722-jcv5-w7mc","GO-2026-4836"],"url":"https://o3.security/vulnerability/CVE-2026-33216","summary":"NATS has MQTT plaintext password disclosure","details":"### Background\n\nNATS.io is a high performance open source pub-sub distributed communication technology, built for the cloud, on-premise, IoT, and edge computing.\n\nThe nats-server provides an MQTT client interface.\n\n### Problem Description\n\nFor MQTT deployments using usercodes/passwords: MQTT passwords are incorrectly classified as a non-authenticating identity statement (JWT) and exposed via monitoring endpoints.\n\n### Affected Versions\n\nAny version before v2.12.6 or v2.11.15\n\n### Workarounds\n\nEnsure monitoring end-points are adequately secured.\n\nBest practice remains to not expose the monitoring endpoint to the Internet or other untrusted network users.","published":"2026-03-25T19:41:55.670Z","modified":"2026-09-11T03:30:13.809285912Z","cvss":{"score":8.6,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N"},"epss":{"score":0.00365,"percentile":0.30202,"asOf":"2026-09-17"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Go","name":"github.com/nats-io/nats-server/v2","fixedVersion":"2.11.15"},{"ecosystem":"Go","name":"github.com/nats-io/nats-server/v2","fixedVersion":"2.12.6"},{"ecosystem":"Go","name":"github.com/nats-io/nats-server","fixedVersion":null}],"fix":{"url":"https://github.com/nats-io/nats-server/commit/b5b63cfc35a57075e09c1f57503d31721bed8099","label":"nats-io/nats-server@b5b63cf"},"references":[{"type":"WEB","url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33216.json"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:21769"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:22347"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:23345"},{"type":"ADVISORY","url":"https://access.redhat.com/security/cve/CVE-2026-33216"},{"type":"ADVISORY","url":"https://advisories.nats.io/CVE/secnote-2026-05.txt"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33216.json"},{"type":"ADVISORY","url":"https://github.com/nats-io/nats-server/security/advisories/GHSA-v722-jcv5-w7mc"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-33216"},{"type":"REPORT","url":"https://bugzilla.redhat.com/show_bug.cgi?id=2451448"},{"type":"FIX","url":"https://github.com/nats-io/nats-server/commit/b5b63cfc35a57075e09c1f57503d31721bed8099"},{"type":"PACKAGE","url":"https://github.com/nats-io/nats-server"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-09-11T03:30:13.809285912Z"}}