CVE-2026-58253

{
  "id": "CVE-2026-58253",
  "sourceIdentifier": "[email protected]",
  "published": "2026-07-08T20:16:54.943",
  "lastModified": "2026-10-25T17:10:00.197",
  "vulnStatus": "Analyzed",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "NATS Server is a high-performance server for NATS.io, the cloud and edge native messaging system. Prior to 2.14.0, 2.12.7, and 2.11.16, when no_auth_user was configured, a parser fast path intended for ordinary client connections could also apply to route or leafnode listeners, allowing an unauthenticated peer to bypass inter-server CONNECT authentication and operate with the privileges associated with that connection type. This issue is fixed in versions 2.14.0, 2.12.7, and 2.11.16."
    },
    {
      "lang": "es",
      "value": "NATS Server es un servidor de alto rendimiento para NATS.io, el sistema de mensajería nativo de la nube y del edge. Antes de las versiones 2.14.0, 2.12.7 y 2.11.16, cuando no_auth_user estaba configurado, una ruta rápida del analizador destinada a conexiones de cliente ordinarias también podía aplicarse a los listeners de ruta o leafnode, permitiendo que un par no autenticado omitiera la autenticación CONNECT entre servidores y operara con los privilegios asociados a ese tipo de conexión. Este problema está solucionado en las versiones 2.14.0, 2.12.7 y 2.11.16."
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "nats-io",
          "product": "nats-server",
          "versions": [
            {
              "version": "< 2.11.16",
              "status": "affected"
            },
            {
              "version": ">= 2.12.0-preview.1, < 2.12.6",
              "status": "affected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "[email protected]",
        "type": "Secondary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:L",
          "baseScore": 8.8,
          "baseSeverity": "HIGH",
          "attackVector": "ADJACENT_NETWORK",
          "attackComplexity": "LOW",
          "privilegesRequired": "NONE",
          "userInteraction": "NONE",
          "scope": "CHANGED",
          "confidentialityImpact": "LOW",
          "integrityImpact": "HIGH",
          "availabilityImpact": "LOW"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 5.3
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-07-09T13:35:15.515260Z",
          "id": "CVE-2026-58253",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-287"
        }
      ]
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "operator": "OR",
          "negate": false,
          "cpeMatch": [
            {
              "vulnerable": true,
              "criteria": "cpe:2.3:a:linuxfoundation:nats-server:*:*:*:*:*:*:*:*",
              "versionEndExcluding": "2.11.16",
              "matchCriteriaId": "64D69F6E-293C-4D5F-92F6-8479213F7727"
            },
            {
              "vulnerable": true,
              "criteria": "cpe:2.3:a:linuxfoundation:nats-server:*:*:*:*:*:*:*:*",
              "versionStartIncluding": "2.12.0",
              "versionEndExcluding": "2.12.7",
              "matchCriteriaId": "DEE2D11B-BD56-4479-A5EB-79F352DA68AB"
            }
          ]
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://github.com/nats-io/nats-server/commit/7b81dd455ea95960090a84858c7662827948d1b6",
      "source": "[email protected]",
      "tags": [
        "Patch"
      ]
    },
    {
      "url": "https://github.com/nats-io/nats-server/commit/8b8e1ad4ceed32321e00d4fc6e76be05bc13bca6",
      "source": "[email protected]",
      "tags": [
        "Patch"
      ]
    },
    {
      "url": "https://github.com/nats-io/nats-server/commit/b86147e81710a52b72a7f7275f91d69f723f5cb3",
      "source": "[email protected]",
      "tags": [
        "Patch"
      ]
    },
    {
      "url": "https://github.com/nats-io/nats-server/releases/tag/v2.11.16",
      "source": "[email protected]",
      "tags": [
        "Release Notes"
      ]
    },
    {
      "url": "https://github.com/nats-io/nats-server/releases/tag/v2.12.7",
      "source": "[email protected]",
      "tags": [
        "Release Notes"
      ]
    },
    {
      "url": "https://github.com/nats-io/nats-server/releases/tag/v2.14.0",
      "source": "[email protected]",
      "tags": [
        "Release Notes"
      ]
    },
    {
      "url": "https://github.com/nats-io/nats-server/security/advisories/GHSA-38x3-76xf-cq45",
      "source": "[email protected]",
      "tags": [
        "Vendor Advisory"
      ]
    }
  ]
}