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pyjwt — security advisory

Type: advisorySources: OSVAdvisory ID: UBUNTU-CVE-2026-102271

PyJWT is a Python implementation of JSON Web Token standards. From 2.4.0 until 2.14.0, PyJWT HMACAlgorithm.prepare_key is affected because asymmetric-key guard relies on textual markers that are absent from DER encoding. This occurs when an application mixes HMAC and asymmetric algorithms and supplies a DER public key as the shared verification key. As a result, PyJWT uses public DER bytes as an HMAC secret. Consequently, an attacker who knows the public key can forge authenticated HMAC tokens. This issue is fixed in version 2.14.0.

Products
pyjwt
Affected versions
1.0.0-0ubuntu1, 1.3.0-1, 1.3.0-1ubuntu0.1, 1.3.0-1ubuntu0.1+esm1, 1.3.0-1ubuntu0.1+esm2, 1.4.2-1.1, 1.5.3+ds1-1, 1.5.3+ds1-1ubuntu0.1, 1.5.3+ds1-1ubuntu0.1+esm1, 1.5.3+ds1-1ubuntu0.1+esm2, 1.7.0-2, 1.7.1-1, 1.7.1-2ubuntu1, 1.7.1-2ubuntu2, 1.7.1-2ubuntu2.1, 1.7.1-2ubuntu2.1+esm1, 1.7.1-2ubuntu2.1+esm2, 2.1.0-1, 2.10.1-2, 2.10.1-3, 2.10.1-3build1, 2.10.1-4, 2.10.1-4ubuntu1, 2.10.1-4ubuntu1.1, 2.12.1-1, 2.13.0-1, 2.3.0-1, 2.3.0-1ubuntu0.1, 2.3.0-1ubuntu0.2, 2.3.0-1ubuntu0.3, 2.3.0-1ubuntu0.4, 2.7.0-1, 2.7.0-1ubuntu0.1, 2.7.0-1ubuntu0.2
Fixed versions
1.3.0-1ubuntu0.1+esm3, 1.5.3+ds1-1ubuntu0.1+esm3, 1.7.1-2ubuntu2.1+esm3, 2.10.1-4ubuntu1.2, 2.13.0-1ubuntu1, 2.3.0-1ubuntu0.5, 2.7.0-1ubuntu0.3
CVEs
CVE-2026-102271
Confirmed fixed CVEs
Not specified
Updated in this feed
1 Nov 2026, 17:54 UTC · Revision 1

Source evidence

UBUNTU-CVE-2026-102271

core-osv · Original source

Published 28 Sept 2026, 21:17 UTC

PyJWT is a Python implementation of JSON Web Token standards. From 2.4.0 until 2.14.0, PyJWT HMACAlgorithm.prepare_key is affected because asymmetric-key guard relies on textual markers that are absent from DER encoding. This occurs when an application mixes HMAC and asymmetric algorithms and supplies a DER public key as the shared verification key. As a result, PyJWT uses public DER bytes as an HMAC secret. Consequently, an attacker who knows the public key can forge authenticated HMAC tokens. This issue is fixed in version 2.14.0.

osv:UBUNTU-CVE-2026-102271

pyjwt

Fixed versions: 1.3.0-1ubuntu0.1+esm3

pyjwt

Fixed versions: 1.5.3+ds1-1ubuntu0.1+esm3

pyjwt

Fixed versions: 1.7.1-2ubuntu2.1+esm3

pyjwt

Fixed versions: 2.3.0-1ubuntu0.5

pyjwt

Fixed versions: 2.7.0-1ubuntu0.3

pyjwt

Fixed versions: 2.13.0-1ubuntu1

pyjwt

Fixed versions: 2.10.1-4ubuntu1.2

Complete source record
{
  "id": "988238cc19ebf35206c46fe40610124574b909008e5a8842a6c0985ecf0d4a4b",
  "url": "https://osv.dev/vulnerability/UBUNTU-CVE-2026-102271",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "UBUNTU-CVE-2026-102271",
    "summary": "PyJWT is a Python implementation of JSON Web Token standards. From 2.4.0 until 2.14.0, PyJWT HMACAlgorithm.prepare_key is affected because asymmetric-key guard relies on textual markers that are absent from DER encoding. This occurs when an application mixes HMAC and asymmetric algorithms and supplies a DER public key as the shared verification key. As a result, PyJWT uses public DER bytes as an HMAC secret. Consequently, an attacker who knows the public key can forge authenticated HMAC tokens. This issue is fixed in version 2.14.0.",
    "evidence": "osv:UBUNTU-CVE-2026-102271",
    "products": [
      {
        "name": {
          "value": "pyjwt",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1.3.0-1ubuntu0.1+esm3",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": [
          {
            "value": "1.0.0-0ubuntu1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "1.3.0-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "1.3.0-1ubuntu0.1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "1.3.0-1ubuntu0.1+esm1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "1.3.0-1ubuntu0.1+esm2",
            "evidence": "/affected/0/versions"
          }
        ]
      },
      {
        "name": {
          "value": "pyjwt",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1.5.3+ds1-1ubuntu0.1+esm3",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": [
          {
            "value": "1.4.2-1.1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "1.5.3+ds1-1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "1.5.3+ds1-1ubuntu0.1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "1.5.3+ds1-1ubuntu0.1+esm1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "1.5.3+ds1-1ubuntu0.1+esm2",
            "evidence": "/affected/1/versions"
          }
        ]
      },
      {
        "name": {
          "value": "pyjwt",
          "evidence": "/affected/2/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1.7.1-2ubuntu2.1+esm3",
            "evidence": "/affected/2/ranges"
          }
        ],
        "affected_versions": [
          {
            "value": "1.7.0-2",
            "evidence": "/affected/2/versions"
          },
          {
            "value": "1.7.1-1",
            "evidence": "/affected/2/versions"
          },
          {
            "value": "1.7.1-2ubuntu1",
            "evidence": "/affected/2/versions"
          },
          {
            "value": "1.7.1-2ubuntu2",
            "evidence": "/affected/2/versions"
          },
          {
            "value": "1.7.1-2ubuntu2.1",
            "evidence": "/affected/2/versions"
          },
          {
            "value": "1.7.1-2ubuntu2.1+esm1",
            "evidence": "/affected/2/versions"
          },
          {
            "value": "1.7.1-2ubuntu2.1+esm2",
            "evidence": "/affected/2/versions"
          }
        ]
      },
      {
        "name": {
          "value": "pyjwt",
          "evidence": "/affected/3/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "2.3.0-1ubuntu0.5",
            "evidence": "/affected/3/ranges"
          }
        ],
        "affected_versions": [
          {
            "value": "1.7.1-2ubuntu2",
            "evidence": "/affected/3/versions"
          },
          {
            "value": "2.1.0-1",
            "evidence": "/affected/3/versions"
          },
          {
            "value": "2.3.0-1",
            "evidence": "/affected/3/versions"
          },
          {
            "value": "2.3.0-1ubuntu0.1",
            "evidence": "/affected/3/versions"
          },
          {
            "value": "2.3.0-1ubuntu0.2",
            "evidence": "/affected/3/versions"
          },
          {
            "value": "2.3.0-1ubuntu0.3",
            "evidence": "/affected/3/versions"
          },
          {
            "value": "2.3.0-1ubuntu0.4",
            "evidence": "/affected/3/versions"
          }
        ]
      },
      {
        "name": {
          "value": "pyjwt",
          "evidence": "/affected/4/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "2.7.0-1ubuntu0.3",
            "evidence": "/affected/4/ranges"
          }
        ],
        "affected_versions": [
          {
            "value": "2.7.0-1",
            "evidence": "/affected/4/versions"
          },
          {
            "value": "2.7.0-1ubuntu0.1",
            "evidence": "/affected/4/versions"
          },
          {
            "value": "2.7.0-1ubuntu0.2",
            "evidence": "/affected/4/versions"
          }
        ]
      },
      {
        "name": {
          "value": "pyjwt",
          "evidence": "/affected/5/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "2.13.0-1ubuntu1",
            "evidence": "/affected/5/ranges"
          }
        ],
        "affected_versions": [
          {
            "value": "2.10.1-4ubuntu1",
            "evidence": "/affected/5/versions"
          },
          {
            "value": "2.12.1-1",
            "evidence": "/affected/5/versions"
          },
          {
            "value": "2.13.0-1",
            "evidence": "/affected/5/versions"
          }
        ]
      },
      {
        "name": {
          "value": "pyjwt",
          "evidence": "/affected/6/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "2.10.1-4ubuntu1.2",
            "evidence": "/affected/6/ranges"
          }
        ],
        "affected_versions": [
          {
            "value": "2.10.1-2",
            "evidence": "/affected/6/versions"
          },
          {
            "value": "2.10.1-3",
            "evidence": "/affected/6/versions"
          },
          {
            "value": "2.10.1-3build1",
            "evidence": "/affected/6/versions"
          },
          {
            "value": "2.10.1-4",
            "evidence": "/affected/6/versions"
          },
          {
            "value": "2.10.1-4ubuntu1",
            "evidence": "/affected/6/versions"
          },
          {
            "value": "2.10.1-4ubuntu1.1",
            "evidence": "/affected/6/versions"
          }
        ]
      }
    ],
    "severity": "high",
    "structured": {
      "id": "UBUNTU-CVE-2026-102271",
      "aliases": [
        "UBUNTU-CVE-2026-102271"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N"
        },
        {
          "type": "Ubuntu",
          "score": "medium"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1.3.0-1ubuntu0.1+esm3"
                }
              ]
            }
          ],
          "package": {
            "name": "pyjwt",
            "purl": "pkg:deb/ubuntu/pyjwt?arch=source&distro=esm-infra-legacy%2Fxenial",
            "ecosystem": "Ubuntu:Pro:16.04:LTS"
          },
          "versions": [
            "1.0.0-0ubuntu1",
            "1.3.0-1",
            "1.3.0-1ubuntu0.1",
            "1.3.0-1ubuntu0.1+esm1",
            "1.3.0-1ubuntu0.1+esm2"
          ],
          "database_specific": {
            "source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-102271.json"
          },
          "ecosystem_specific": {
            "binaries": [
              {
                "binary_name": "python-jwt",
                "binary_version": "1.3.0-1ubuntu0.1+esm3"
              },
              {
                "binary_name": "python3-jwt",
                "binary_version": "1.3.0-1ubuntu0.1+esm3"
              }
            ],
            "availability": "Available with Ubuntu Pro with Legacy support add-on: https://ubuntu.com/pro"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1.5.3+ds1-1ubuntu0.1+esm3"
                }
              ]
            }
          ],
          "package": {
            "name": "pyjwt",
            "purl": "pkg:deb/ubuntu/pyjwt?arch=source&distro=esm-infra%2Fbionic",
            "ecosystem": "Ubuntu:Pro:18.04:LTS"
          },
          "versions": [
            "1.4.2-1.1",
            "1.5.3+ds1-1",
            "1.5.3+ds1-1ubuntu0.1",
            "1.5.3+ds1-1ubuntu0.1+esm1",
            "1.5.3+ds1-1ubuntu0.1+esm2"
          ],
          "database_specific": {
            "source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-102271.json"
          },
          "ecosystem_specific": {
            "binaries": [
              {
                "binary_name": "python-jwt",
                "binary_version": "1.5.3+ds1-1ubuntu0.1+esm3"
              },
              {
                "binary_name": "python3-jwt",
                "binary_version": "1.5.3+ds1-1ubuntu0.1+esm3"
              }
            ],
            "availability": "Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1.7.1-2ubuntu2.1+esm3"
                }
              ]
            }
          ],
          "package": {
            "name": "pyjwt",
            "purl": "pkg:deb/ubuntu/pyjwt?arch=source&distro=esm-infra%2Ffocal",
            "ecosystem": "Ubuntu:Pro:20.04:LTS"
          },
          "versions": [
            "1.7.0-2",
            "1.7.1-1",
            "1.7.1-2ubuntu1",
            "1.7.1-2ubuntu2",
            "1.7.1-2ubuntu2.1",
            "1.7.1-2ubuntu2.1+esm1",
            "1.7.1-2ubuntu2.1+esm2"
          ],
          "database_specific": {
            "source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-102271.json"
          },
          "ecosystem_specific": {
            "binaries": [
              {
                "binary_name": "python3-jwt",
                "binary_version": "1.7.1-2ubuntu2.1+esm3"
              }
            ],
            "availability": "Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "2.3.0-1ubuntu0.5"
                }
              ]
            }
          ],
          "package": {
            "name": "pyjwt",
            "purl": "pkg:deb/ubuntu/pyjwt?arch=source&distro=jammy",
            "ecosystem": "Ubuntu:22.04:LTS"
          },
          "versions": [
            "1.7.1-2ubuntu2",
            "2.1.0-1",
            "2.3.0-1",
            "2.3.0-1ubuntu0.1",
            "2.3.0-1ubuntu0.2",
            "2.3.0-1ubuntu0.3",
            "2.3.0-1ubuntu0.4"
          ],
          "database_specific": {
            "source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-102271.json"
          },
          "ecosystem_specific": {
            "binaries": [
              {
                "binary_name": "python3-jwt",
                "binary_version": "2.3.0-1ubuntu0.5"
              }
            ],
            "availability": "No subscription required"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "2.7.0-1ubuntu0.3"
                }
              ]
            }
          ],
          "package": {
            "name": "pyjwt",
            "purl": "pkg:deb/ubuntu/pyjwt?arch=source&distro=noble",
            "ecosystem": "Ubuntu:24.04:LTS"
          },
          "versions": [
            "2.7.0-1",
            "2.7.0-1ubuntu0.1",
            "2.7.0-1ubuntu0.2"
          ],
          "database_specific": {
            "source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-102271.json"
          },
          "ecosystem_specific": {
            "binaries": [
              {
                "binary_name": "python3-jwt",
                "binary_version": "2.7.0-1ubuntu0.3"
              }
            ],
            "availability": "No subscription required"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "2.13.0-1ubuntu1"
                }
              ]
            }
          ],
          "package": {
            "name": "pyjwt",
            "purl": "pkg:deb/ubuntu/pyjwt?arch=source&distro=stonking",
            "ecosystem": "Ubuntu:26.10"
          },
          "versions": [
            "2.10.1-4ubuntu1",
            "2.12.1-1",
            "2.13.0-1"
          ],
          "database_specific": {
            "source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-102271.json"
          },
          "ecosystem_specific": {
            "binaries": [
              {
                "binary_name": "python3-jwt",
                "binary_version": "2.13.0-1ubuntu1"
              }
            ],
            "availability": "No subscription required"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "2.10.1-4ubuntu1.2"
                }
              ]
            }
          ],
          "package": {
            "name": "pyjwt",
            "purl": "pkg:deb/ubuntu/pyjwt?arch=source&distro=resolute",
            "ecosystem": "Ubuntu:26.04:LTS"
          },
          "versions": [
            "2.10.1-2",
            "2.10.1-3",
            "2.10.1-3build1",
            "2.10.1-4",
            "2.10.1-4ubuntu1",
            "2.10.1-4ubuntu1.1"
          ],
          "database_specific": {
            "source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-102271.json"
          },
          "ecosystem_specific": {
            "binaries": [
              {
                "binary_name": "python3-jwt",
                "binary_version": "2.10.1-4ubuntu1.2"
              }
            ],
            "availability": "No subscription required"
          }
        }
      ],
      "modified": "2026-10-27T11:56:51.082278802Z",
      "provider": "osv",
      "upstream": [
        "CVE-2026-102271"
      ],
      "references": [
        "https://ubuntu.com/security/CVE-2026-102271",
        "https://www.cve.org/CVERecord?id=CVE-2026-102271",
        "https://github.com/jpadilla/pyjwt/security/advisories/GHSA-p4g4-x82p-q773",
        "https://github.com/jpadilla/pyjwt/commit/2798504fa2663364573cf2d1043d8d7fef389499",
        "https://github.com/jpadilla/pyjwt/releases/tag/2.14.0",
        "https://ubuntu.com/security/notices/USN-8916-2",
        "https://ubuntu.com/security/notices/USN-8916-1"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2026-102271",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 461462,
  "published_at": "2026-09-28T21:17:00+00:00"
}