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CVE-2026-77166

Estado: AplazadaBaja (2.4)—

The emoji field in the page emoji update endpoint does not properly validate user input. By injecting long text and line breaks, the sidebar layout becomes broken and can hide other items.

CVSS

Probabilidad de explotación (EPSS)

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.

CWE-840 (sin validación) en endpoint web con interacción de usuario (UI:R, PR:H). El texto describe manipulación de UI pero sin confirmación de ejecución de código o acceso no autorizado.

Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Restrict File and Directory PermissionsRemote Data StorageEncrypt Sensitive InformationApplication Isolation and SandboxingExploit ProtectionUpdate Software

CWE

Referencias

JSON original (NVD)

Mostrar
{
  "id": "CVE-2026-77166",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-77166",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-09-21T18:42:53.420732Z"
        }
      }
    ],
    "cvssMetricV30": [
      {
        "type": "Secondary",
        "source": "support@hackerone.com",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.0",
          "baseScore": 2.4,
          "attackVector": "NETWORK",
          "baseSeverity": "LOW",
          "vectorString": "CVSS:3.0/AV:N/AC:L/PR:H/UI:R/S:U/C:N/I:L/A:N",
          "integrityImpact": "LOW",
          "userInteraction": "REQUIRED",
          "attackComplexity": "LOW",
          "availabilityImpact": "NONE",
          "privilegesRequired": "HIGH",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 1.4,
        "exploitabilityScore": 0.9
      }
    ]
  },
  "affected": [
    {
      "source": "support@hackerone.com",
      "affectedData": [
        {
          "vendor": "Nextcloud",
          "product": "Collectives",
          "versions": [
            {
              "status": "affected",
              "version": "3.2.1",
              "versionType": "semver",
              "lessThanOrEqual": "3.5.0"
            }
          ],
          "defaultStatus": "unaffected"
        }
      ]
    }
  ],
  "published": "2026-09-21T16:17:24.013",
  "references": [
    {
      "url": "https://hackerone.com/reports/3599470",
      "source": "support@hackerone.com"
    },
    {
      "url": "https://hackerone.com/reports/3599470",
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"
    }
  ],
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "support@hackerone.com",
      "description": [
        {
          "lang": "en",
          "value": "CWE-840"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "The emoji field in the page emoji update endpoint does not properly validate user input. By injecting long text and line breaks, the sidebar layout becomes broken and can hide other items."
    }
  ],
  "lastModified": "2026-09-22T20:00:03.713",
  "sourceIdentifier": "support@hackerone.com"
}