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NATS has MQTT plaintext password disclosure

Type: advisorySources: OSV

NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Prior to versions 2.11.15 and 2.12.6, for MQTT deployments using usercodes/passwords: MQTT passwords are incorrectly classified as a non-authenticating identity statement (JWT) and exposed via monitoring endpoints. Versions 2.11.14 and 2.12.6 contain a fix. As a workaround, ensure monitoring end-points are adequately secured. Best practice remains to not expose the monitoring endpoint to the Internet or other untrusted network users.

Products
Not specified
Affected versions
Not specified
Fixed versions
Not specified
CVEs
CVE-2026-33216
Confirmed fixed CVEs
Not specified
Updated in this feed
4 Nov 2026, 09:08 UTC · Revision 1

Source evidence

NATS has MQTT plaintext password disclosure

core-osv · Original source

Published 25 Mar 2026, 19:41 UTC

NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Prior to versions 2.11.15 and 2.12.6, for MQTT deployments using usercodes/passwords: MQTT passwords are incorrectly classified as a non-authenticating identity statement (JWT) and exposed via monitoring endpoints. Versions 2.11.14 and 2.12.6 contain a fix. As a workaround, ensure monitoring end-points are adequately secured. Best practice remains to not expose the monitoring endpoint to the Internet or other untrusted network users.

osv:CVE-2026-33216
Complete source record
{
  "id": "516769ed80fc5108e54210475c5ad2f1569f93affd0a9968643c12952f8b9a66",
  "url": "https://osv.dev/vulnerability/CVE-2026-33216",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "NATS has MQTT plaintext password disclosure",
    "summary": "NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Prior to versions 2.11.15 and 2.12.6, for MQTT deployments using usercodes/passwords: MQTT passwords are incorrectly classified as a non-authenticating identity statement (JWT) and exposed via monitoring endpoints. Versions 2.11.14 and 2.12.6 contain a fix. As a workaround, ensure monitoring end-points are adequately secured. Best practice remains to not expose the monitoring endpoint to the Internet or other untrusted network users.",
    "evidence": "osv:CVE-2026-33216",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-33216",
      "aliases": [
        "BIT-nats-2026-33216",
        "CVE-2026-33216",
        "GHSA-v722-jcv5-w7mc",
        "GO-2026-4836"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/nats-io/nats-server",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "bef17e1d9de6574fae0eabe1798db0d4529834e4"
                },
                {
                  "introduced": "fc6ec648d806652d282d2f0edb6cb9f22c895572"
                },
                {
                  "fixed": "0e0639058e0d2d8fce0cc34941f9897da152ab32"
                },
                {
                  "fixed": "b5b63cfc35a57075e09c1f57503d31721bed8099"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:linuxfoundation:nats-server:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "2.11.15"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "cpe": "cpe:2.3:a:linuxfoundation:nats-server:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "2.12.0"
                      },
                      {
                        "fixed": "2.12.6"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "range": [
                      {
                        "fixed": "b5b63cfc35a57075e09c1f57503d31721bed8099"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
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          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-33216.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:34.386512582Z",
      "provider": "osv",
      "references": [
        "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33216.json",
        "https://access.redhat.com/errata/RHSA-2026:21769",
        "https://access.redhat.com/errata/RHSA-2026:22347",
        "https://access.redhat.com/errata/RHSA-2026:23345",
        "https://access.redhat.com/security/cve/CVE-2026-33216",
        "https://advisories.nats.io/CVE/secnote-2026-05.txt",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33216.json",
        "https://github.com/nats-io/nats-server/security/advisories/GHSA-v722-jcv5-w7mc",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-33216",
        "https://bugzilla.redhat.com/show_bug.cgi?id=2451448",
        "https://github.com/nats-io/nats-server/commit/b5b63cfc35a57075e09c1f57503d31721bed8099"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-256"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33216.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-33216",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 501335,
  "published_at": "2026-03-25T19:41:55.67+00:00"
}