FKIE_CVE-2026-102272

Vulnerability from fkie_nvd - Published: 2026-09-28 21:17 - Updated: 2026-09-30 19:56
Severity
7.4 (High) - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
Summary
PyJWT is a Python implementation of JSON Web Token standards. From 2.13.0 until 2.14.0, HMACAlgorithm.prepare_key in jwt/algorithms.py is affected because raw-JWK detector does not normalize accepted Unicode byte-order marks before checking for JSON. This occurs when a public JWK is prefixed with a UTF-8 BOM and used in a mixed-algorithm verification path. As a result, public JWK bypasses asymmetric-key detection and becomes the HMAC secret. Consequently, an attacker who knows the public key can forge authenticated tokens. This issue is fixed in version 2.14.0.
References
security-advisories@github.comhttps://github.com/jpadilla/pyjwt/commit/180783930de91876bc0d601f826a1f2956057291
security-advisories@github.comhttps://github.com/jpadilla/pyjwt/releases/tag/2.14.0
security-advisories@github.comhttps://github.com/jpadilla/pyjwt/security/advisories/GHSA-r6x4-923q-g947
134c704f-9b21-4f2e-91b3-4a467353bcc0https://github.com/jpadilla/pyjwt/security/advisories/GHSA-r6x4-923q-g947
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "pyjwt",
          "vendor": "jpadilla",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 2.13.0, \u003c 2.14.0"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "PyJWT is a Python implementation of JSON Web Token standards. From 2.13.0 until 2.14.0, HMACAlgorithm.prepare_key in jwt/algorithms.py is affected because raw-JWK detector does not normalize accepted Unicode byte-order marks before checking for JSON. This occurs when a public JWK is prefixed with a UTF-8 BOM and used in a mixed-algorithm verification path. As a result, public JWK bypasses asymmetric-key detection and becomes the HMAC secret. Consequently, an attacker who knows the public key can forge authenticated tokens. This issue is fixed in version 2.14.0."
    }
  ],
  "id": "CVE-2026-102272",
  "lastModified": "2026-09-30T19:56:45.443",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "HIGH",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 7.4,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 2.2,
        "impactScore": 5.2,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-102272",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-09-29T14:45:38.333972Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-09-28T21:17:15.280",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/jpadilla/pyjwt/commit/180783930de91876bc0d601f826a1f2956057291"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/jpadilla/pyjwt/releases/tag/2.14.0"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/jpadilla/pyjwt/security/advisories/GHSA-r6x4-923q-g947"
    },
    {
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "url": "https://github.com/jpadilla/pyjwt/security/advisories/GHSA-r6x4-923q-g947"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Awaiting Analysis",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-347"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Secondary"
    }
  ]
}



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