CVE-2026-48796

{
  "id": "CVE-2026-48796",
  "sourceIdentifier": "[email protected]",
  "published": "2026-08-18T22:16:52.280",
  "lastModified": "2026-11-09T20:10:00.200",
  "vulnStatus": "Deferred",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "CefSharp provides .NET bindings for the Chromium Embedded Framework for Windows Forms and Windows Presentation Foundation applications. Prior to version 148.0.90, CefSharp/SchemeHandler/FolderSchemeHandlerFactory.cs used filePath.StartsWith(rootFolder, StringComparison.OrdinalIgnoreCase) to decide whether a decoded and canonicalized request path remained inside rootFolder. That raw prefix test did not enforce a directory boundary, so a request such as ..%2fwww2/secret.txt could escape a configured www directory into a sibling www2 directory whose path shared the same string prefix. Applications that register FolderSchemeHandlerFactory for a custom scheme or an HTTP or HTTPS scheme can therefore serve local files outside the intended root when an attacker can cause the embedded browser to request the crafted URL. The issue affects both Unix-style paths such as /tmp/app/www2 and Windows paths such as C:\\app\\www2, and the fix appends a directory separator to the normalized root before comparison while rejecting null bytes and alternate data stream syntax. This issue is fixed in version 148.0.90."
    },
    {
      "lang": "es",
      "value": "CefSharp proporciona enlaces .NET para el Chromium Embedded Framework para aplicaciones de Windows Forms y Windows Presentation Foundation. Antes de la versión 148.0.90, CefSharp/SchemeHandler/FolderSchemeHandlerFactory.cs utilizaba filePath.StartsWith(rootFolder, StringComparison.OrdinalIgnoreCase) para decidir si una ruta de solicitud decodificada y canonizada permanecía dentro de rootFolder. Esa prueba de prefijo sin procesar no aplicaba un límite de directorio, por lo que una solicitud como ..%2fwww2/secret.txt podría escapar de un directorio www configurado a un directorio www2 hermano cuya ruta compartía el mismo prefijo de cadena. Las aplicaciones que registran FolderSchemeHandlerFactory para un esquema personalizado o un esquema HTTP o HTTPS pueden, por lo tanto, servir archivos locales fuera de la raíz prevista cuando un atacante puede hacer que el navegador incrustado solicite la URL manipulada. El problema afecta tanto a las rutas de estilo Unix como /tmp/app/www2 como a las rutas de Windows como C:\\app\\www2, y la solución añade un separador de directorio a la raíz normalizada antes de la comparación, al tiempo que rechaza los bytes nulos y la sintaxis de flujo de datos alternativo. Este problema se corrige en la versión 148.0.90."
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "cefsharp",
          "product": "CefSharp",
          "versions": [
            {
              "version": "< 148.0.90",
              "status": "affected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "[email protected]",
        "type": "Secondary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N",
          "baseScore": 5.3,
          "baseSeverity": "MEDIUM",
          "attackVector": "NETWORK",
          "attackComplexity": "HIGH",
          "privilegesRequired": "NONE",
          "userInteraction": "REQUIRED",
          "scope": "UNCHANGED",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "NONE",
          "availabilityImpact": "NONE"
        },
        "exploitabilityScore": 1.6,
        "impactScore": 3.6
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-08-19T18:03:47.436022Z",
          "id": "CVE-2026-48796",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-22"
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://github.com/cefsharp/CefSharp/commit/3475c7ef14119f67ec3720866bb3e4b1c6c68632",
      "source": "[email protected]"
    },
    {
      "url": "https://github.com/cefsharp/CefSharp/releases/tag/v148.0.90",
      "source": "[email protected]"
    },
    {
      "url": "https://github.com/cefsharp/CefSharp/security/advisories/GHSA-85jm-cwp2-mvpv",
      "source": "[email protected]"
    }
  ]
}