{"id":"CVE-2026-33215","aliases":["BIT-nats-2026-33215","GHSA-fcjp-h8cc-6879","GO-2026-4833"],"url":"https://o3.security/vulnerability/CVE-2026-33215","summary":"NATS is vulnerable to MQTT hijacking via Client ID","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\nSessions and Messages can by hijacked via MQTT Client ID malfeasance.\n\n### Affected Versions\n\nAny version before v2.12.6 or v2.11.15\n\n### Workarounds\n\nNone.\n\n### Resources\n\n * This document is canonically: <https://advisories.nats.io/CVE/secnote-2026-06.txt>\n * GHSA advisory: <https://github.com/nats-io/nats-server/security/advisories/GHSA-fcjp-h8cc-6879>\n * MITRE CVE entry: <https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-33215>","published":"2026-03-24T20:55:53.455Z","modified":"2026-08-12T03:51:33.665970043Z","cvss":{"score":6.5,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:L"},"epss":{"score":0.0024,"percentile":0.15332,"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"}],"fix":null,"references":[{"type":"ADVISORY","url":"https://advisories.nats.io/CVE/secnote-2026-06.tx"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33215.json"},{"type":"ADVISORY","url":"https://github.com/nats-io/nats-server/security/advisories/GHSA-fcjp-h8cc-6879"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-33215"},{"type":"PACKAGE","url":"https://github.com/nats-io/nats-server"},{"type":"WEB","url":"https://pkg.go.dev/vuln/GO-2026-4833"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:33.665970043Z"}}