Vulnerability-Lookup

Vulnerability from bitnami_vulndb

Published

2026-03-27 17:45

Modified

2026-03-27 18:14

Summary

NATS allows MQTT clients to bypass ACL checks

Details

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, when using ACLs on message subjects, these ACLs were not applied in the $MQTT.> namespace, allowing MQTT clients to bypass ACL checks for MQTT subjects. Versions 2.11.15 and 2.12.6 contain a fix. No known workarounds are available.

JSON

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{
  "affected": [
    {
      "package": {
        "ecosystem": "Bitnami",
        "name": "nats",
        "purl": "pkg:bitnami/nats"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.11.15"
            },
            {
              "introduced": "2.12.0"
            },
            {
              "fixed": "2.12.6"
            }
          ],
          "type": "SEMVER"
        }
      ],
      "severity": [
        {
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N",
          "type": "CVSS_V3"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-33217"
  ],
  "database_specific": {
    "cpes": [
      "cpe:2.3:a:nats:nats_server:*:*:*:*:*:go:*:*"
    ],
    "severity": "Medium"
  },
  "details": "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, when using ACLs on message subjects, these ACLs were not applied in the `$MQTT.\u003e` namespace, allowing MQTT clients to bypass ACL checks for MQTT subjects. Versions 2.11.15 and 2.12.6 contain a fix. No known workarounds are available.",
  "id": "BIT-nats-2026-33217",
  "modified": "2026-03-27T18:14:10.313Z",
  "published": "2026-03-27T17:45:15.042Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://advisories.nats.io/CVE/secnote-2026-07.txt"
    },
    {
      "type": "WEB",
      "url": "https://github.com/nats-io/nats-server/security/advisories/GHSA-jxxm-27vp-c3m5"
    },
    {
      "type": "WEB",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-33217"
    }
  ],
  "schema_version": "1.6.2",
  "summary": "NATS allows MQTT clients to bypass ACL checks"
}

CVE-2026-33217 (GCVE-0-2026-33217)

Vulnerability from cvelistv5 – Published: 2026-03-25 19:43 – Updated: 2026-03-25 20:08

Title

NATS allows MQTT clients to bypass ACL checks

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, when using ACLs on message subjects, these ACLs were not applied in the `$MQTT.>` namespace, allowing MQTT clients to bypass ACL checks for MQTT subjects. Versions 2.11.15 and 2.12.6 contain a fix. No known workarounds are available.

Severity ?

7.1 (High)


                        
                          CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N

CWE

CWE-863 - Incorrect Authorization

Assigner

GitHub_M

References

URL

Tags

	https://github.com/nats-io/nats-server/security/a…	x_refsource_CONFIRM
	https://advisories.nats.io/CVE/secnote-2026-07.txt	x_refsource_MISC

Impacted products

	Vendor	Product	Version
	nats-io	nats-server	Affected: < 2.11.15 Affected: >= 2.12.0-RC.1, < 2.12.6

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-33217",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-03-25T20:07:59.832372Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-03-25T20:08:22.861Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "nats-server",
          "vendor": "nats-io",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 2.11.15"
            },
            {
              "status": "affected",
              "version": "\u003e= 2.12.0-RC.1, \u003c 2.12.6"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "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, when using ACLs on message subjects, these ACLs were not applied in the `$MQTT.\u003e` namespace, allowing MQTT clients to bypass ACL checks for MQTT subjects. Versions 2.11.15 and 2.12.6 contain a fix. No known workarounds are available."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 7.1,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "LOW",
            "integrityImpact": "HIGH",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-863",
              "description": "CWE-863: Incorrect Authorization",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-03-25T19:49:48.934Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/nats-io/nats-server/security/advisories/GHSA-jxxm-27vp-c3m5",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/nats-io/nats-server/security/advisories/GHSA-jxxm-27vp-c3m5"
        },
        {
          "name": "https://advisories.nats.io/CVE/secnote-2026-07.txt",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://advisories.nats.io/CVE/secnote-2026-07.txt"
        }
      ],
      "source": {
        "advisory": "GHSA-jxxm-27vp-c3m5",
        "discovery": "UNKNOWN"
      },
      "title": "NATS allows MQTT clients to bypass ACL checks"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-33217",
    "datePublished": "2026-03-25T19:43:40.969Z",
    "dateReserved": "2026-03-17T23:23:58.314Z",
    "dateUpdated": "2026-03-25T20:08:22.861Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

Action not permitted

Vulnerability from bitnami_vulndb

CVE-2026-33217 (GCVE-0-2026-33217)

Tags

Sightings

Nomenclature