CVE-2026-27889

Estado: ModificadaAlta (7.5)—

NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Starting in version 2.2.0 and prior to versions 2.11.14 and 2.12.5, a missing sanity check on a WebSockets frame could trigger a server panic in the nats-server. This happens before authentication, and so is exposed to anyone who can connect to the websockets port. Versions 2.11.14 and 2.12.5 contains a fix. A workaround is available. The vulnerability only affects deployments which use WebSockets and which expose the network port to untrusted end-points. If one is able to do so, a defense in depth of restricting either of these will mitigate the attack.

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Puntuación base: 7.5

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.84%
Percentil entre todas las CVEs puntuadas: 57
Fecha de la puntuación: 6/10/2026

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

ExplotaciónT1190 Exploit Public-Facing Applicationinitial access60 %
Impacto principalT1499 Endpoint Denial of Serviceimpact55 %

Inferido por reglas deterministas a partir del vector CVSS y la CWE. Solo orientativo.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Filter Network Traffic Vulnerability Scanning Privileged Account Management Network Segmentation Limit Access to Resource Over Network Application Isolation and Sandboxing

Tecnologías afectadas (1)

Linuxfoundation — Nats-server

CWE

CWE-190
CWE-1286

Referencias

JSON original (NVD)

Mostrar

{
  "id": "CVE-2026-27889",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-27889",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-03-25T20:06:22.827675Z"
        }
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "security-advisories@github.com",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.5,
          "attackVector": "NETWORK",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 3.6,
        "exploitabilityScore": 3.9
      },
      {
        "type": "Secondary",
        "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.5,
          "attackVector": "NETWORK",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 3.6,
        "exploitabilityScore": 3.9
      }
    ]
  },
  "affected": [
    {
      "source": "security-advisories@github.com",
      "affectedData": [
        {
          "vendor": "nats-io",
          "product": "nats-server",
          "versions": [
            {
              "status": "affected",
              "version": ">= 2.2.0, < 2.11.14"
            },
            {
              "status": "affected",
              "version": ">= 2.12.0, < 2.12.5"
            }
          ]
        }
      ]
    },
    {
      "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c",
      "affectedData": [
        {
          "cpes": [
            "cpe:/a:redhat:multicluster_globalhub:1.4::el9"
          ],
          "vendor": "Red Hat",
          "product": "Multicluster Global Hub 1.4.5",
          "versions": [
            {
              "status": "unaffected",
              "version": "1779579439",
              "lessThan": "*",
              "versionType": "rpm"
            }
          ],
          "packageName": "multicluster-globalhub/multicluster-globalhub-grafana-rhel9",
          "collectionURL": "https://catalog.redhat.com/software/containers/",
          "defaultStatus": "affected"
        },
        {
          "cpes": [
            "cpe:/a:redhat:multicluster_globalhub:1.6::el9"
          ],
          "vendor": "Red Hat",
          "product": "Multicluster Global Hub 1.6.5",
          "versions": [
            {
              "status": "unaffected",
              "version": "1780167118",
              "lessThan": "*",
              "versionType": "rpm"
            }
          ],
          "packageName": "multicluster-globalhub/multicluster-globalhub-grafana-rhel9",
          "collectionURL": "https://catalog.redhat.com/software/containers/",
          "defaultStatus": "affected"
        },
        {
          "cpes": [
            "cpe:/a:redhat:multicluster_globalhub:1.5::el9"
          ],
          "vendor": "Red Hat",
          "product": "Red Hat multicluster global hub 1.5.3",
          "versions": [
            {
              "status": "unaffected",
              "version": "1778867753",
              "lessThan": "*",
              "versionType": "rpm"
            }
          ],
          "packageName": "multicluster-globalhub/multicluster-globalhub-grafana-rhel9",
          "collectionURL": "https://catalog.redhat.com/software/containers/",
          "defaultStatus": "affected"
        },
        {
          "cpes": [
            "cpe:/a:redhat:openshift:4"
          ],
          "vendor": "Red Hat",
          "product": "Red Hat OpenShift Container Platform 4",
          "packageName": "openshift4/oc-mirror-plugin-rhel9",
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "defaultStatus": "unaffected"
        }
      ]
    }
  ],
  "published": "2026-03-25T20:16:27.210",
  "references": [
    {
      "url": "https://advisories.nats.io/CVE/secnote-2026-03.txt",
      "tags": [
        "Mitigation",
        "Vendor Advisory"
      ],
      "source": "security-advisories@github.com"
    },
    {
      "url": "https://github.com/nats-io/nats-server/security/advisories/GHSA-pq2q-rcw4-3hr6",
      "tags": [
        "Mitigation",
        "Vendor Advisory"
      ],
      "source": "security-advisories@github.com"
    },
    {
      "url": "https://access.redhat.com/errata/RHSA-2026:21769",
      "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"
    },
    {
      "url": "https://access.redhat.com/errata/RHSA-2026:22347",
      "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"
    },
    {
      "url": "https://access.redhat.com/errata/RHSA-2026:23345",
      "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"
    },
    {
      "url": "https://access.redhat.com/security/cve/CVE-2026-27889",
      "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"
    },
    {
      "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2451447",
      "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"
    },
    {
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-27889.json",
      "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"
    }
  ],
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "security-advisories@github.com",
      "description": [
        {
          "lang": "en",
          "value": "CWE-190"
        }
      ]
    },
    {
      "type": "Secondary",
      "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c",
      "description": [
        {
          "lang": "en",
          "value": "CWE-1286"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Starting in version 2.2.0 and prior to versions 2.11.14 and 2.12.5, a missing sanity check on a WebSockets frame could trigger a server panic in the nats-server.  This happens before authentication, and so is exposed to anyone who can connect to the websockets port. Versions 2.11.14 and 2.12.5 contains a fix. A workaround is available. The vulnerability only affects deployments which use WebSockets and which expose the network port to untrusted end-points. If one is able to do so, a defense in depth of restricting either of these will mitigate the attack."
    },
    {
      "lang": "es",
      "value": "NATS-Server es un servidor de alto rendimiento para NATS.io, un sistema de mensajería nativo de la nube y del borde. A partir de la versión 2.2.0 y antes de las versiones 2.11.14 y 2.12.5, una comprobación de cordura faltante en un marco de WebSockets podría desencadenar un pánico del servidor en el nats-server. Esto ocurre antes de la autenticación, y por lo tanto está expuesto a cualquiera que pueda conectarse al puerto de websockets. Las versiones 2.11.14 y 2.12.5 contienen una corrección. Una solución alternativa está disponible. La vulnerabilidad solo afecta a las implementaciones que usan WebSockets y que exponen el puerto de red a puntos finales no confiables. Si uno es capaz de hacerlo, una defensa en profundidad de restringir cualquiera de estos mitigará el ataque."
    }
  ],
  "lastModified": "2026-09-09T13:19:10.343",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:linuxfoundation:nats-server:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "6681EAC6-5A1D-4F3A-926C-F7BEB21791AA",
              "versionEndExcluding": "2.11.14",
              "versionStartIncluding": "2.2.0"
            },
            {
              "criteria": "cpe:2.3:a:linuxfoundation:nats-server:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "B141DA72-3502-4746-A246-EE1087C993F4",
              "versionEndExcluding": "2.12.5",
              "versionStartIncluding": "2.12.0"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "security-advisories@github.com"
}