« Back to list

CVE-2016-10555

Status: ModifiedMedium (6.5)—💥 PoC

Since "algorithm" isn't enforced in jwt.decode()in jwt-simple 0.3.0 and earlier, a malicious user could choose what algorithm is sent sent to the server. If the server is expecting RSA but is sent HMAC-SHA with RSA's public key, the server will think the public key is actually an HMAC private key. This could be used to forge any data an attacker wants.

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).

💥 Public exploits

Exploit code or detection templates are publicly available. This is not the same as confirmed active exploitation (KEV), but it raises the risk: patch with priority.

⚠️ GitHub proofs of concept are not verified: some are fake or contain malware. Never run them outside an isolated lab.

Affected technologies (1)

Jwt-simple Project — Jwt-simple

CWEs

References

Raw JSON (NVD)

Show
{
  "id": "CVE-2016-10555",
  "cveTags": [],
  "metrics": {
    "cvssMetricV2": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "version": "2.0",
          "baseScore": 4,
          "accessVector": "NETWORK",
          "vectorString": "AV:N/AC:L/Au:S/C:N/I:P/A:N",
          "authentication": "SINGLE",
          "integrityImpact": "PARTIAL",
          "accessComplexity": "LOW",
          "availabilityImpact": "NONE",
          "confidentialityImpact": "NONE"
        },
        "acInsufInfo": false,
        "impactScore": 2.9,
        "baseSeverity": "MEDIUM",
        "obtainAllPrivilege": false,
        "exploitabilityScore": 8,
        "obtainUserPrivilege": false,
        "obtainOtherPrivilege": false,
        "userInteractionRequired": false
      }
    ],
    "cvssMetricV30": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.0",
          "baseScore": 6.5,
          "attackVector": "NETWORK",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "NONE",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 3.6,
        "exploitabilityScore": 2.8
      }
    ]
  },
  "affected": [
    {
      "source": "support@hackerone.com",
      "affectedData": [
        {
          "vendor": "HackerOne",
          "product": "jwt-simple node module",
          "versions": [
            {
              "status": "affected",
              "version": "<=0.3.0"
            }
          ]
        }
      ]
    }
  ],
  "published": "2018-05-31T20:29:02.067",
  "references": [
    {
      "url": "https://auth0.com/blog/2015/03/31/critical-vulnerabilities-in-json-web-token-libraries/",
      "tags": [
        "Broken Link",
        "Third Party Advisory"
      ],
      "source": "support@hackerone.com"
    },
    {
      "url": "https://github.com/hokaccha/node-jwt-simple/pull/14",
      "tags": [
        "Issue Tracking",
        "Third Party Advisory"
      ],
      "source": "support@hackerone.com"
    },
    {
      "url": "https://github.com/hokaccha/node-jwt-simple/pull/16",
      "tags": [
        "Issue Tracking",
        "Third Party Advisory"
      ],
      "source": "support@hackerone.com"
    },
    {
      "url": "https://nodesecurity.io/advisories/87",
      "tags": [
        "Third Party Advisory"
      ],
      "source": "support@hackerone.com"
    },
    {
      "url": "https://auth0.com/blog/2015/03/31/critical-vulnerabilities-in-json-web-token-libraries/",
      "tags": [
        "Broken Link",
        "Third Party Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://github.com/hokaccha/node-jwt-simple/pull/14",
      "tags": [
        "Issue Tracking",
        "Third Party Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://github.com/hokaccha/node-jwt-simple/pull/16",
      "tags": [
        "Issue Tracking",
        "Third Party Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://nodesecurity.io/advisories/87",
      "tags": [
        "Third Party Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    }
  ],
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "support@hackerone.com",
      "description": [
        {
          "lang": "en",
          "value": "CWE-20"
        }
      ]
    },
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "CWE-310"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "Since \"algorithm\" isn't enforced in jwt.decode()in jwt-simple 0.3.0 and earlier, a malicious user could choose what algorithm is sent sent to the server. If the server is expecting RSA but is sent HMAC-SHA with RSA's public key, the server will think the public key is actually an HMAC private key. This could be used to forge any data an attacker wants."
    },
    {
      "lang": "es",
      "value": "Como \"algorithm\" no se aplica en jwt.decode() en jwt-simple en versiones 0.3.0 y anteriores, un usuario malicioso podría elegir qué algoritmo se envía al servidor. Si el servidor espera RSA pero recibe HMAC-SHA con la clave pública RSA, el servidor pensará que la clave pública es, en realidad, una clave privada HMAC. Esto podría emplearse para falsificar cualquier dato que quiera un atacante."
    }
  ],
  "lastModified": "2026-06-17T00:39:55.730",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:jwt-simple_project:jwt-simple:*:*:*:*:*:node.js:*:*",
              "vulnerable": true,
              "matchCriteriaId": "FB7173F7-05CB-4AF1-866F-BC98BB7996DE",
              "versionEndIncluding": "0.3.0"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "support@hackerone.com"
}