FKIE_CVE-2026-27889

Vulnerability from fkie_nvd - Published: 2026-03-25 20:16 - Updated: 2026-03-26 17:13
Severity ?
7.5 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Summary
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.
References
security-advisories@github.comhttps://advisories.nats.io/CVE/secnote-2026-03.txtMitigation, Vendor Advisory
security-advisories@github.comhttps://github.com/nats-io/nats-server/security/advisories/GHSA-pq2q-rcw4-3hr6Mitigation, Vendor Advisory
Impacted products
Vendor Product Version
linuxfoundation nats-server *
linuxfoundation nats-server *
To clipboard 

{
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:linuxfoundation:nats-server:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "6681EAC6-5A1D-4F3A-926C-F7BEB21791AA",
              "versionEndExcluding": "2.11.14",
              "versionStartIncluding": "2.2.0",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:a:linuxfoundation:nats-server:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "B141DA72-3502-4746-A246-EE1087C993F4",
              "versionEndExcluding": "2.12.5",
              "versionStartIncluding": "2.12.0",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "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 mensajer\u00eda nativo de la nube y del borde. A partir de la versi\u00f3n 2.2.0 y antes de las versiones 2.11.14 y 2.12.5, una comprobaci\u00f3n de cordura faltante en un marco de WebSockets podr\u00eda desencadenar un p\u00e1nico del servidor en el nats-server. Esto ocurre antes de la autenticaci\u00f3n, y por lo tanto est\u00e1 expuesto a cualquiera que pueda conectarse al puerto de websockets. Las versiones 2.11.14 y 2.12.5 contienen una correcci\u00f3n. Una soluci\u00f3n alternativa est\u00e1 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 mitigar\u00e1 el ataque."
    }
  ],
  "id": "CVE-2026-27889",
  "lastModified": "2026-03-26T17:13:16.140",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 7.5,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 3.6,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-03-25T20:16:27.210",
  "references": [
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Mitigation",
        "Vendor Advisory"
      ],
      "url": "https://advisories.nats.io/CVE/secnote-2026-03.txt"
    },
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Mitigation",
        "Vendor Advisory"
      ],
      "url": "https://github.com/nats-io/nats-server/security/advisories/GHSA-pq2q-rcw4-3hr6"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-190"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Primary"
    }
  ]
}


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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

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.