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CVE-2026-6239

Status: DeferredMedium (6.8)—

A stack‑based buffer overflow vulnerability exists in Tapo C520WS v2 in the ONVIF CreateUsers service, where the device fails to properly validate the number of XML user nodes during request processing. An authenticated attacker can send a specially crafted ONVIF request containing an excessive number of user entries to trigger memory corruption.

Successful exploitation may cause the ONVIF management service to terminate unexpectedly, resulting in a denial‑of‑service (DoS) condition that disrupts device configuration and management functions.

CVSS

Exploitation probability (EPSS)

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

Affected technologies (1)

⚠ AI-inferred from the description — NVD hasn't analyzed this CVE yet, these aren't verified CPEs.

Tp-link — Tapo C520wsAI

CWEs

References

Raw JSON (NVD)

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{
  "id": "CVE-2026-6239",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-6239",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-06-08T13:07:25.793532Z"
        }
      }
    ],
    "cvssMetricV40": [
      {
        "type": "Secondary",
        "source": "f23511db-6c3e-4e32-a477-6aa17d310630",
        "cvssData": {
          "Safety": "NOT_DEFINED",
          "version": "4.0",
          "Recovery": "NOT_DEFINED",
          "baseScore": 6.8,
          "Automatable": "NOT_DEFINED",
          "attackVector": "ADJACENT",
          "baseSeverity": "MEDIUM",
          "valueDensity": "NOT_DEFINED",
          "vectorString": "CVSS:4.0/AV:A/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
          "exploitMaturity": "NOT_DEFINED",
          "providerUrgency": "NOT_DEFINED",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "attackRequirements": "NONE",
          "privilegesRequired": "HIGH",
          "subIntegrityImpact": "NONE",
          "vulnIntegrityImpact": "NONE",
          "integrityRequirement": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "subAvailabilityImpact": "NONE",
          "vulnAvailabilityImpact": "HIGH",
          "availabilityRequirement": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "subConfidentialityImpact": "NONE",
          "vulnConfidentialityImpact": "NONE",
          "confidentialityRequirement": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "vulnerabilityResponseEffort": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED"
        }
      }
    ]
  },
  "affected": [
    {
      "source": "f23511db-6c3e-4e32-a477-6aa17d310630",
      "affectedData": [
        {
          "vendor": "TP-Link Systems Inc.",
          "product": "Tapo C520WS v2",
          "versions": [
            {
              "status": "affected",
              "version": "0",
              "lessThan": "1.2.6 Build 260528",
              "versionType": "custom"
            }
          ],
          "defaultStatus": "unaffected"
        }
      ]
    }
  ],
  "published": "2026-06-06T00:16:40.977",
  "references": [
    {
      "url": "https://www.tp-link.com/en/support/download/tapo-c520ws/#Firmware-Release-Notes",
      "source": "f23511db-6c3e-4e32-a477-6aa17d310630"
    },
    {
      "url": "https://www.tp-link.com/us/support/download/tapo-c520ws/#Firmware-Release-Notes",
      "source": "f23511db-6c3e-4e32-a477-6aa17d310630"
    },
    {
      "url": "https://www.tp-link.com/us/support/faq/5120/",
      "source": "f23511db-6c3e-4e32-a477-6aa17d310630"
    }
  ],
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "f23511db-6c3e-4e32-a477-6aa17d310630",
      "description": [
        {
          "lang": "en",
          "value": "CWE-121"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "A stack‑based\nbuffer overflow vulnerability exists in Tapo C520WS v2 in the ONVIF CreateUsers service, where\nthe device fails to properly validate the number of XML user nodes during\nrequest processing. An authenticated attacker can send a specially crafted\nONVIF request containing an excessive number of user entries to trigger memory\ncorruption.\n\n\n\n\n\n\n\n\n\nSuccessful\nexploitation may cause the ONVIF management service to terminate unexpectedly,\nresulting in a denial‑of‑service (DoS) condition that disrupts device\nconfiguration and management functions."
    },
    {
      "lang": "es",
      "value": "Una vulnerabilidad de desbordamiento de búfer basado en pila existe en Tapo C520WS v2 en el servicio ONVIF CreateUsers, donde el dispositivo no valida correctamente el número de nodos de usuario XML durante el procesamiento de solicitudes. Un atacante autenticado puede enviar una solicitud ONVIF especialmente diseñada que contiene un número excesivo de entradas de usuario para desencadenar la corrupción de memoria.\n\nLa explotación exitosa puede hacer que el servicio de gestión ONVIF termine inesperadamente, lo que resulta en una condición de denegación de servicio (DoS) que interrumpe las funciones de configuración y gestión del dispositivo."
    }
  ],
  "lastModified": "2026-07-23T07:10:00.113",
  "sourceIdentifier": "f23511db-6c3e-4e32-a477-6aa17d310630"
}