Apache APISIX: JWT Algorithm Confusion allows authentication bypass

{
  "id": "f925d3f8845e38c7be66c7fd0e53bd43e5a191e717efa492d1a4476ba3f381dd",
  "url": "https://osv.dev/vulnerability/CVE-2026-39999",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Apache APISIX: JWT Algorithm Confusion allows authentication bypass",
    "summary": "Authentication Bypass by Spoofing vulnerability in Apache APISIX. The attacker can completely bypass authentication capitalising on certain configurations of jwt-auth plugin. This issue affects Apache APISIX: from v2.2 through v3.16.0. Users are recommended to upgrade to version v3.17.0, which fixes the issue.",
    "evidence": "osv:CVE-2026-39999",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-39999",
      "aliases": [
        "BIT-apisix-2026-39999",
        "CVE-2026-39999"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/apache/apisix",
              "type": "GIT",
              "events": [
                {
                  "introduced": "e8dcf3793ca40b30047406ac51a79a500356f67b"
                },
                {
                  "fixed": "9ef2ecab67f652d38365049613610ef649bb4ad0"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:apache:apisix:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "2.2"
                      },
                      {
                        "fixed": "3.17.0"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-39999.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:28.373140154Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/39xxx/CVE-2026-39999.json",
        "https://lists.apache.org/thread/nfopt8cnxd3k0rs1oxtr7lzxrdw4mojq",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-39999"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-290"
        ],
        "cna_assigner": "apache",
        "unresolved_ranges": [
          {
            "extracted_events": [
              {
                "range": [
                  {
                    "introduced": "2.2"
                  },
                  {
                    "last_affected": "3.16.0"
                  }
                ],
                "source": "AFFECTED_FIELD",
                "strategy": "StandardRange"
              }
            ]
          }
        ],
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/39xxx/CVE-2026-39999.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-39999",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 495330,
  "published_at": "2026-06-19T13:07:50.893+00:00"
}