GHSA-VPRV-35VV-Q339

Vulnerability from github – Published: 2026-03-24 21:45 – Updated: 2026-03-24 21:45
VLAI?
Summary
NATS has pre-auth server panic via leafnode handling
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 allows hub/spoke topologies using "leafnode" connections by other nats-servers.

Problem Description

A client which can connect to the leafnode port can crash the nats-server with a certain malformed message pre-authentication.

Affected Versions

Any version before v2.12.6 or v2.11.15

Workarounds

  1. Disable leafnode support if not needed.
  2. Restrict network connections to your leafnode port, if plausible without compromising the service offered.

References

Severity ?
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Show details on source website
To clipboard 

{
  "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-2026-33218"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-20"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-03-24T21:45:29Z",
    "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 allows hub/spoke topologies using \"leafnode\" connections by other nats-servers.\n\n### Problem Description\n\nA client which can connect to the leafnode port can crash the nats-server with a certain malformed message pre-authentication.\n\n### Affected Versions\n\nAny version before v2.12.6 or v2.11.15\n\n### Workarounds\n\n1. Disable leafnode support if not needed.\n2. Restrict network connections to your leafnode port, if plausible without compromising the service offered.\n\n### References\n\n * This document is canonically: \u003chttps://advisories.nats.io/CVE/secnote-2026-10.txt\u003e\n * GHSA advisory: \u003chttps://github.com/nats-io/nats-server/security/advisories/GHSA-vprv-35vv-q339\u003e\n * MITRE CVE entry: \u003chttps://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-33218\u003e",
  "id": "GHSA-vprv-35vv-q339",
  "modified": "2026-03-24T21:45:29Z",
  "published": "2026-03-24T21:45:29Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/nats-io/nats-server/security/advisories/GHSA-vprv-35vv-q339"
    },
    {
      "type": "WEB",
      "url": "https://advisories.nats.io/CVE/secnote-2026-10.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:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "NATS has pre-auth server panic via leafnode handling"
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




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.