python-authlib — security advisory

{
  "id": "717d4165241d55e5691679bdb559893a2e6927802a0616eb97d8fe2302b58ef7",
  "url": "https://osv.dev/vulnerability/UBUNTU-CVE-2026-28802",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "UBUNTU-CVE-2026-28802",
    "summary": "Authlib is a Python library which builds OAuth and OpenID Connect servers. From version 1.6.5 to before version 1.6.7, previous tests involving passing a malicious JWT containing alg: none and an empty signature was passing the signature verification step without any changes to the application code when a failure was expected.. This issue has been patched in version 1.6.7.",
    "evidence": "osv:UBUNTU-CVE-2026-28802",
    "products": [
      {
        "name": {
          "value": "python-authlib",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "1.5.1-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "1.5.2-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "1.6.0-1",
            "evidence": "/affected/0/versions"
          }
        ]
      }
    ],
    "severity": "critical",
    "structured": {
      "id": "UBUNTU-CVE-2026-28802",
      "aliases": [
        "UBUNTU-CVE-2026-28802"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:P"
        },
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N"
        },
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
        },
        {
          "type": "Ubuntu",
          "score": "medium"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "python-authlib",
            "purl": "pkg:deb/ubuntu/python-authlib?arch=source&distro=questing",
            "ecosystem": "Ubuntu:25.10"
          },
          "versions": [
            "1.5.1-1",
            "1.5.2-1",
            "1.6.0-1"
          ],
          "database_specific": {
            "source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-28802.json"
          },
          "ecosystem_specific": {
            "binaries": [
              {
                "binary_name": "python3-authlib",
                "binary_version": "1.6.0-1"
              }
            ]
          }
        }
      ],
      "modified": "2026-10-27T04:17:54.861784776Z",
      "provider": "osv",
      "upstream": [
        "CVE-2026-28802"
      ],
      "references": [
        "https://ubuntu.com/security/CVE-2026-28802",
        "https://www.cve.org/CVERecord?id=CVE-2026-28802",
        "https://github.com/authlib/authlib/commit/a61c2acb807496e67f32051b5f1b1d5ccf8f0a75",
        "https://github.com/authlib/authlib/commit/b87c32ed07b8ae7f805873e1c9cafd1016761df7",
        "https://github.com/authlib/authlib/security/advisories/GHSA-7wc2-qxgw-g8gg"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2026-28802",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/2/score"
  },
  "source_id": "core-osv",
  "document_id": 460324,
  "published_at": "2026-03-06T07:16:00+00:00"
}