CVE-2021-42663

Estado: ModificadaMedia (4.3)—💥 Exploit

An HTML injection vulnerability exists in Sourcecodester Online Event Booking and Reservation System in PHP/MySQL via the msg parameter to /event-management/index.php. An attacker can leverage this vulnerability in order to change the visibility of the website. Once the target user clicks on a given link he will display the content of the HTML code of the attacker's choice.

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N
Puntuación base: 4.3

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 3.85%
Percentil entre todas las CVEs puntuadas: 90
Fecha de la puntuación: 7/10/2026

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).

💥 Exploits públicos

Hay código de explotación o plantillas de detección públicos. No es lo mismo que explotación activa confirmada (KEV), pero aumenta el riesgo: parchee con prioridad.

Plantilla de Nuclei (detección automática y masiva) · Sourcecodester Online Event Booking and Reservation System 2.3.0 - Cross-Site Scripting
Prueba de concepto en GitHub (no verificada) · Lista de pruebas de concepto en GitHub

⚠️ Las pruebas de concepto de GitHub no están verificadas: algunas son falsas o contienen malware. No las ejecute nunca fuera de un laboratorio aislado.

Tecnologías afectadas (1)

Online Event Booking AND Reservation System Project — Online Event Booking AND Reservation System

CWE

CWE-79

Referencias

JSON original (NVD)

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{
  "id": "CVE-2021-42663",
  "cveTags": [],
  "metrics": {
    "cvssMetricV2": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "version": "2.0",
          "baseScore": 4.3,
          "accessVector": "NETWORK",
          "vectorString": "AV:N/AC:M/Au:N/C:P/I:N/A:N",
          "authentication": "NONE",
          "integrityImpact": "NONE",
          "accessComplexity": "MEDIUM",
          "availabilityImpact": "NONE",
          "confidentialityImpact": "PARTIAL"
        },
        "acInsufInfo": false,
        "impactScore": 2.9,
        "baseSeverity": "MEDIUM",
        "obtainAllPrivilege": false,
        "exploitabilityScore": 8.6,
        "obtainUserPrivilege": false,
        "obtainOtherPrivilege": false,
        "userInteractionRequired": true
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 4.3,
          "attackVector": "NETWORK",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N",
          "integrityImpact": "NONE",
          "userInteraction": "REQUIRED",
          "attackComplexity": "LOW",
          "availabilityImpact": "NONE",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "LOW"
        },
        "impactScore": 1.4,
        "exploitabilityScore": 2.8
      }
    ]
  },
  "affected": [
    {
      "source": "cve@mitre.org",
      "affectedData": [
        {
          "vendor": "n/a",
          "product": "n/a",
          "versions": [
            {
              "status": "affected",
              "version": "n/a"
            }
          ]
        }
      ]
    }
  ],
  "published": "2021-11-05T13:15:07.630",
  "references": [
    {
      "url": "https://github.com/TheHackingRabbi/CVE-2021-42663",
      "tags": [
        "Exploit",
        "Third Party Advisory"
      ],
      "source": "cve@mitre.org"
    },
    {
      "url": "https://www.sourcecodester.com/php/14241/online-event-booking-and-reservation-system-phpmysql.html",
      "tags": [
        "Product",
        "Third Party Advisory"
      ],
      "source": "cve@mitre.org"
    },
    {
      "url": "https://github.com/TheHackingRabbi/CVE-2021-42663",
      "tags": [
        "Exploit",
        "Third Party Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://www.sourcecodester.com/php/14241/online-event-booking-and-reservation-system-phpmysql.html",
      "tags": [
        "Product",
        "Third Party Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    }
  ],
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "CWE-79"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "An HTML injection vulnerability exists in Sourcecodester Online Event Booking and Reservation System in PHP/MySQL via the msg parameter to /event-management/index.php. An attacker can leverage this vulnerability in order to change the visibility of the website. Once the target user clicks on a given link he will display the content of the HTML code of the attacker's choice."
    },
    {
      "lang": "es",
      "value": "Se presenta una vulnerabilidad de inyección de HTML en Sourcecodester Online Event Booking and Reservation System en PHP/MySQL por medio del parámetro msg en el archivo /event-management/index.php. Un atacante puede aprovechar esta vulnerabilidad para cambiar la visibilidad del sitio web. Una vez que el usuario objetivo haga clic en un enlace determinado, mostrará el contenido del código HTML que el atacante elija"
    }
  ],
  "lastModified": "2026-06-17T04:09:55.850",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:online_event_booking_and_reservation_system_project:online_event_booking_and_reservation_system:2.3.0:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "E052D7DA-B44E-48D6-B44B-8BB974D47DFF"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "cve@mitre.org"
}