GHSA-JXXM-27VP-C3M5

Vulnerability from github – Published: 2026-03-24 21:44 – Updated: 2026-03-24 21:45
VLAI?
Summary
NATS allows MQTT clients to bypass ACL checks
Details

Background

NATS.io is a high performance open source pub-sub distributed communication technology, built for the cloud, on-premise, IoT, and edge computing.

The nats-server provides an MQTT client interface.

Problem Description

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.

Affected Versions

Any version before v2.12.6 or v2.11.15

Workarounds

None.

Severity ?
7.1 (High)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N
Show details on source website
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{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/nats-io/nats-server/v2"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.11.15"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/nats-io/nats-server/v2"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.12.0-RC.1"
            },
            {
              "fixed": "2.12.6"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-33217"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-863"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-03-24T21:44:17Z",
    "nvd_published_at": null,
    "severity": "HIGH"
  },
  "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\nWhen 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.\n\n### Affected Versions\n\nAny version before v2.12.6 or v2.11.15\n\n### Workarounds\n\nNone.",
  "id": "GHSA-jxxm-27vp-c3m5",
  "modified": "2026-03-24T21:45:03Z",
  "published": "2026-03-24T21:44:17Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/nats-io/nats-server/security/advisories/GHSA-jxxm-27vp-c3m5"
    },
    {
      "type": "WEB",
      "url": "https://advisories.nats.io/CVE/secnote-2026-07.txt"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/nats-io/nats-server"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "NATS allows MQTT clients to bypass ACL checks"
}


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  • 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.
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  • 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.