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CVE-2017-6638

Status: ModifiedHigh (7.8)—

A vulnerability in how DLL files are loaded with Cisco AnyConnect Secure Mobility Client for Windows could allow an authenticated, local attacker to install and run an executable file with privileges equivalent to the Microsoft Windows SYSTEM account. The vulnerability is due to incomplete input validation of path and file names of a DLL file before it is loaded. An attacker could exploit this vulnerability by creating a malicious DLL file and installing it in a specific system directory.

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A successful exploit could allow the attacker to execute commands on the underlying Microsoft Windows host with privileges equivalent to the SYSTEM account. The attacker would need valid user credentials to exploit this vulnerability. This vulnerability affects all Cisco AnyConnect Secure Mobility Client for Windows software versions prior to 4.4.02034. Cisco Bug IDs: CSCvc97928.

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)

Cisco — Anyconnect Secure Mobility Client

CWEs

References

Raw JSON (NVD)

Show
{
  "id": "CVE-2017-6638",
  "cveTags": [],
  "metrics": {
    "cvssMetricV2": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "version": "2.0",
          "baseScore": 7.2,
          "accessVector": "LOCAL",
          "vectorString": "AV:L/AC:L/Au:N/C:C/I:C/A:C",
          "authentication": "NONE",
          "integrityImpact": "COMPLETE",
          "accessComplexity": "LOW",
          "availabilityImpact": "COMPLETE",
          "confidentialityImpact": "COMPLETE"
        },
        "acInsufInfo": false,
        "impactScore": 10,
        "baseSeverity": "HIGH",
        "obtainAllPrivilege": false,
        "exploitabilityScore": 3.9,
        "obtainUserPrivilege": false,
        "obtainOtherPrivilege": false,
        "userInteractionRequired": false
      }
    ],
    "cvssMetricV30": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.0",
          "baseScore": 7.8,
          "attackVector": "LOCAL",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 1.8
      }
    ]
  },
  "affected": [
    {
      "source": "psirt@cisco.com",
      "affectedData": [
        {
          "vendor": "n/a",
          "product": "Cisco AnyConnect Local Privilege Escalation Vulnerability",
          "versions": [
            {
              "status": "affected",
              "version": "Cisco AnyConnect Local Privilege Escalation Vulnerability"
            }
          ]
        }
      ]
    }
  ],
  "published": "2017-06-08T13:29:00.423",
  "references": [
    {
      "url": "http://www.securityfocus.com/bid/98938",
      "tags": [
        "Third Party Advisory",
        "VDB Entry"
      ],
      "source": "psirt@cisco.com"
    },
    {
      "url": "http://www.securitytracker.com/id/1038627",
      "source": "psirt@cisco.com"
    },
    {
      "url": "https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170607-anyconnect",
      "tags": [
        "Vendor Advisory"
      ],
      "source": "psirt@cisco.com"
    },
    {
      "url": "http://www.securityfocus.com/bid/98938",
      "tags": [
        "Third Party Advisory",
        "VDB Entry"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "http://www.securitytracker.com/id/1038627",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170607-anyconnect",
      "tags": [
        "Vendor Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    }
  ],
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "psirt@cisco.com",
      "description": [
        {
          "lang": "en",
          "value": "CWE-264"
        }
      ]
    },
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "CWE-20"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "A vulnerability in how DLL files are loaded with Cisco AnyConnect Secure Mobility Client for Windows could allow an authenticated, local attacker to install and run an executable file with privileges equivalent to the Microsoft Windows SYSTEM account. The vulnerability is due to incomplete input validation of path and file names of a DLL file before it is loaded. An attacker could exploit this vulnerability by creating a malicious DLL file and installing it in a specific system directory. A successful exploit could allow the attacker to execute commands on the underlying Microsoft Windows host with privileges equivalent to the SYSTEM account. The attacker would need valid user credentials to exploit this vulnerability. This vulnerability affects all Cisco AnyConnect Secure Mobility Client for Windows software versions prior to 4.4.02034. Cisco Bug IDs: CSCvc97928."
    },
    {
      "lang": "es",
      "value": "Una vulnerabilidad en cómo los archivos DLL son cargados con AnyConnect Secure Mobility Client de Cisco para Windows, podría permitir a un atacante local autenticado instalar y ejecutar un archivo ejecutable con privilegios equivalentes a la cuenta SYSTEM de Microsoft Windows. La vulnerabilidad es debido a la comprobación de entrada incompleta de la ruta (path) de acceso y los nombres de archivo de un archivo DLL antes que sea cargado. Un atacante podría explotar esta vulnerabilidad mediante la creación de un archivo DLL malicioso e instalarlo en un directorio específico del sistema. Una explotación apropiada podría permitir al atacante ejecutar comandos en el host subyacente de Microsoft Windows con privilegios equivalentes a la cuenta SYSTEM. El atacante necesitaría credenciales de usuario válidas para explotar esta vulnerabilidad. Esta vulnerabilidad afecta a todas las versiones de software AnyConnect Secure Mobility Client de Cisco para Windows versiones anteriores a 4.4.02034. ID de bug de Cisco: CSCvc97928."
    }
  ],
  "lastModified": "2026-06-17T01:22:42.203",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:cisco:anyconnect_secure_mobility_client:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "02ECDB88-47A5-4CF9-80CC-9804995B0B7F",
              "versionEndIncluding": "4.4.00243"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "psirt@cisco.com"
}