FKIE_CVE-2017-11424

Vulnerability from fkie_nvd - Published: 2017-08-24 16:29 - Updated: 2026-06-17 01:01
Severity
7.5 (High) - CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Summary
In PyJWT 1.5.0 and below the `invalid_strings` check in `HMACAlgorithm.prepare_key` does not account for all PEM encoded public keys. Specifically, the PKCS1 PEM encoded format would be allowed because it is prefaced with the string `-----BEGIN RSA PUBLIC KEY-----` which is not accounted for. This enables symmetric/asymmetric key confusion attacks against users using the PKCS1 PEM encoded public keys, which would allow an attacker to craft JWTs from scratch.
References
security@duo.comhttp://www.debian.org/security/2017/dsa-3979Third Party Advisory
security@duo.comhttps://github.com/jpadilla/pyjwt/pull/277Issue Tracking, Patch, Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108http://www.debian.org/security/2017/dsa-3979Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://github.com/jpadilla/pyjwt/pull/277Issue Tracking, Patch, Third Party Advisory
Impacted products
Vendor Product Version
pyjwt_project pyjwt *
debian debian_linux 8.0
debian debian_linux 9.0
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "n/a",
          "vendor": "n/a",
          "versions": [
            {
              "status": "affected",
              "version": "n/a"
            }
          ]
        }
      ],
      "source": "security@duo.com"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
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              "criteria": "cpe:2.3:a:pyjwt_project:pyjwt:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "2ED2491D-3EA6-4348-BABC-A1752F717260",
              "versionEndIncluding": "1.5.0",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    },
    {
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              "vulnerable": true
            },
            {
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              "matchCriteriaId": "DEECE5FC-CACF-4496-A3E7-164736409252",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In PyJWT 1.5.0 and below the `invalid_strings` check in `HMACAlgorithm.prepare_key` does not account for all PEM encoded public keys. Specifically, the PKCS1 PEM encoded format would be allowed because it is prefaced with the string `-----BEGIN RSA PUBLIC KEY-----` which is not accounted for. This enables symmetric/asymmetric key confusion attacks against users using the PKCS1 PEM encoded public keys, which would allow an attacker to craft JWTs from scratch."
    },
    {
      "lang": "es",
      "value": "En PyJWT 1.5.0 y anteriores, la comprobaci\u00f3n `invalid_strings` en `HMACAlgorithm.prepare_key` no da cuenta de todas las claves p\u00fablicas codificadas PEM. Espec\u00edficamente, el formato codificado PKCS1 PEM se permitir\u00eda porque va precedido por la cadena `-----BEGIN RSA PUBLIC KEY-----`, la cual no se tiene en cuenta. Esto permite ataques sim\u00e9tricos/asim\u00e9tricos de confusi\u00f3n de claves contra usuarios que empleen las claves p\u00fablicas PKCS1 PEM, que permitir\u00edan que un atacante manipulase JWT desde cero."
    }
  ],
  "id": "CVE-2017-11424",
  "lastModified": "2026-06-17T01:01:47.717",
  "metrics": {
    "cvssMetricV2": [
      {
        "acInsufInfo": false,
        "baseSeverity": "MEDIUM",
        "cvssData": {
          "accessComplexity": "LOW",
          "accessVector": "NETWORK",
          "authentication": "NONE",
          "availabilityImpact": "NONE",
          "baseScore": 5.0,
          "confidentialityImpact": "NONE",
          "integrityImpact": "PARTIAL",
          "vectorString": "AV:N/AC:L/Au:N/C:N/I:P/A:N",
          "version": "2.0"
        },
        "exploitabilityScore": 10.0,
        "impactScore": 2.9,
        "obtainAllPrivilege": false,
        "obtainOtherPrivilege": false,
        "obtainUserPrivilege": false,
        "source": "nvd@nist.gov",
        "type": "Primary",
        "userInteractionRequired": false
      }
    ],
    "cvssMetricV30": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 7.5,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "NONE",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N",
          "version": "3.0"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 3.6,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
    ]
  },
  "published": "2017-08-24T16:29:00.197",
  "references": [
    {
      "source": "security@duo.com",
      "tags": [
        "Third Party Advisory"
      ],
      "url": "http://www.debian.org/security/2017/dsa-3979"
    },
    {
      "source": "security@duo.com",
      "tags": [
        "Issue Tracking",
        "Patch",
        "Third Party Advisory"
      ],
      "url": "https://github.com/jpadilla/pyjwt/pull/277"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
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    },
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      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Issue Tracking",
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        "Third Party Advisory"
      ],
      "url": "https://github.com/jpadilla/pyjwt/pull/277"
    }
  ],
  "sourceIdentifier": "security@duo.com",
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "NVD-CWE-noinfo"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}



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