PyJWT: PyJWKClient still amplifies unauthenticated JWKS fetches on unknown kid values (incomplete fix of CVE-2026-48524)

{
  "id": "49c7574365ba82ffc4dde954570080c4e55e9bbd5a6e8f945143fd1b1b2e7c13",
  "url": "https://osv.dev/vulnerability/CVE-2026-101917",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "PyJWT: PyJWKClient still amplifies unauthenticated JWKS fetches on unknown kid values (incomplete fix of CVE-2026-48524)",
    "summary": "PyJWT is a Python implementation of JSON Web Token standards. Prior to 2.14.0, PyJWT get_signing_key_from_jwt is affected because unknown kid misses force refreshes without a negative cache or minimum refresh interval. This occurs when unauthenticated tokens repeatedly use the same unknown kid or varying kid values absent from the cached JWKS. As a result, each cache miss causes PyJWKClient to refresh the JWKS. Consequently, attacker traffic can amplify outbound requests to the configured JWKS endpoint. This issue is fixed in version 2.14.0.",
    "evidence": "osv:CVE-2026-101917",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-101917",
      "aliases": [
        "CVE-2026-101917",
        "GHSA-2gx3-rcp4-g85q",
        "PYSEC-2026-4140"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/jpadilla/pyjwt",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "c6fe464b356ff4b1ebc9ba62172d331a40aa27df"
                },
                {
                  "fixed": "ba4853a75fb9676362da17f67d0f64bd18afd4e1"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:pyjwt_project:pyjwt:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "2.14.0"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "range": [
                      {
                        "fixed": "ba4853a75fb9676362da17f67d0f64bd18afd4e1"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "c6fe464b356ff4b1ebc9ba62172d331a40aa27df"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "2.14.0"
                  }
                ]
              }
            }
          ],
          "versions": [
            "2.13.0",
            "2.12.1",
            "2.12.0",
            "2.11.0",
            "2.10.1",
            "2.10.0",
            "2.9.0",
            "2.8.0",
            "2.7.0",
            "2.6.0",
            "2.5.0",
            "2.4.0",
            "2.3.0",
            "2.2.0",
            "2.1.0",
            "2.0.1",
            "2.0.0",
            "2.0.0a2",
            "2.0.0a1",
            "1.7.1",
            "1.7.0",
            "1.6.4",
            "1.6.3",
            "1.6.1",
            "1.6.0",
            "1.5.3",
            "1.5.2",
            "1.5.1",
            "1.5.0",
            "1.4.2",
            "1.4.1",
            "1.4.0",
            "1.3.0",
            "1.2.0",
            "1.1.0",
            "1.0.1",
            "1.0.0",
            "0.4.3",
            "0.4.2",
            "0.4.1",
            "0.4.0",
            "0.3.2",
            "0.3.1",
            "0.3.0",
            "0.2.3",
            "0.2.2",
            "0.2.0",
            "0.1.9",
            "0.1.6"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-101917.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:50.192887801Z",
      "provider": "osv",
      "references": [
        "https://github.com/jpadilla/pyjwt/releases/tag/2.14.0",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/101xxx/CVE-2026-101917.json",
        "https://github.com/jpadilla/pyjwt/security/advisories/GHSA-2gx3-rcp4-g85q",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-101917",
        "https://github.com/jpadilla/pyjwt/commit/ba4853a75fb9676362da17f67d0f64bd18afd4e1"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-770"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/101xxx/CVE-2026-101917.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-101917",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 518938,
  "published_at": "2026-09-28T20:07:44.237+00:00"
}