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CVE-2016-3957

Status: ModifiedCritical (9.8)—

The secure_load function in gluon/utils.py in web2py before 2.14.2 uses pickle.loads to deserialize session information stored in cookies, which might allow remote attackers to execute arbitrary code by leveraging knowledge of encryption_key.

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)

Web2py — Web2py

CWEs

References

Raw JSON (NVD)

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{
  "id": "CVE-2016-3957",
  "cveTags": [],
  "metrics": {
    "cvssMetricV2": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "version": "2.0",
          "baseScore": 7.5,
          "accessVector": "NETWORK",
          "vectorString": "AV:N/AC:L/Au:N/C:P/I:P/A:P",
          "authentication": "NONE",
          "integrityImpact": "PARTIAL",
          "accessComplexity": "LOW",
          "availabilityImpact": "PARTIAL",
          "confidentialityImpact": "PARTIAL"
        },
        "acInsufInfo": true,
        "impactScore": 6.4,
        "baseSeverity": "HIGH",
        "obtainAllPrivilege": false,
        "exploitabilityScore": 10,
        "obtainUserPrivilege": false,
        "obtainOtherPrivilege": false,
        "userInteractionRequired": false
      }
    ],
    "cvssMetricV30": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.0",
          "baseScore": 9.8,
          "attackVector": "NETWORK",
          "baseSeverity": "CRITICAL",
          "vectorString": "CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 3.9
      }
    ]
  },
  "affected": [
    {
      "source": "cve@mitre.org",
      "affectedData": [
        {
          "vendor": "n/a",
          "product": "n/a",
          "versions": [
            {
              "status": "affected",
              "version": "n/a"
            }
          ]
        }
      ]
    }
  ],
  "published": "2018-02-06T18:29:00.400",
  "references": [
    {
      "url": "https://devco.re/blog/2017/01/03/web2py-unserialize-code-execution-CVE-2016-3957/",
      "tags": [
        "Exploit",
        "Technical Description",
        "Third Party Advisory"
      ],
      "source": "cve@mitre.org"
    },
    {
      "url": "https://github.com/web2py/web2py/blob/R-2.14.1/gluon/utils.py#L200",
      "tags": [
        "Third Party Advisory"
      ],
      "source": "cve@mitre.org"
    },
    {
      "url": "https://usn.ubuntu.com/4030-1/",
      "source": "cve@mitre.org"
    },
    {
      "url": "https://devco.re/blog/2017/01/03/web2py-unserialize-code-execution-CVE-2016-3957/",
      "tags": [
        "Exploit",
        "Technical Description",
        "Third Party Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://github.com/web2py/web2py/blob/R-2.14.1/gluon/utils.py#L200",
      "tags": [
        "Third Party Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://usn.ubuntu.com/4030-1/",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    }
  ],
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "CWE-502"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "The secure_load function in gluon/utils.py in web2py before 2.14.2 uses pickle.loads to deserialize session information stored in cookies, which might allow remote attackers to execute arbitrary code by leveraging knowledge of encryption_key."
    },
    {
      "lang": "es",
      "value": "La función secure_load en gluon/utils.py en web2py, en versiones anteriores a la 2.14.2, emplea pickle.loads para deserializar información de sesión almacenada en cookies. Esto podría permitir que atacantes remotos ejecuten código arbitrario aprovechando el conocimiento de encryption_key."
    }
  ],
  "lastModified": "2026-06-17T00:46:38.307",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:web2py:web2py:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "AFE64C05-496E-4D7D-A659-5F376D249FAC",
              "versionEndExcluding": "2.14.2"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "cve@mitre.org"
}