{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "4.38.0"
              },
              {
                "fixed": "4.39.20"
              }
            ],
            "source": "AFFECTED_FIELD"
          },
          "events": [
            {
              "introduced": "a53395fd7e4f40f0ac26e29a0b722c52c3015a06"
            },
            {
              "fixed": "1b524f7f4bbf7b5637f4c6b98f4f66fd4b4aed91"
            }
          ],
          "repo": "https://github.com/authelia/authelia",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-hjj4-hfjm-fmrj"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-178",
      "CWE-307"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/47xxx/CVE-2026-47203.json"
  },
  "details": "Authelia is an open-source authentication and authorization server providing two-factor authentication and single sign-on (SSO) for applications via a web portal. In versions 4.38.0 through 4.39.19, when a user authenticates via Basic Auth (i.e via the `Authorization` header with the `Basic` scheme) on the authz verification endpoint, Authelia takes the username directly from the `Authorization` header and passes it as is to the regulation system for ban checking and attempt recording. LDAP treats usernames case insensitively : `john`, `John`, and `JOHN` all bind as the same user. But the regulation SQL queries treat the lookup of these values in certain scenarios as case sensitive. This allows each variation of a usernames case to have its own ban bucket. Upgrade to 4.39.20 to receive a patch. As a workaround, explicitly disable the basic auth mechanism.",
  "id": "CVE-2026-47203",
  "modified": "2026-07-08T05:38:01.815449093Z",
  "published": "2026-06-19T20:19:47.903Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/47xxx/CVE-2026-47203.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/authelia/authelia/security/advisories/GHSA-hjj4-hfjm-fmrj"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-47203"
    },
    {
      "type": "FIX",
      "url": "https://github.com/authelia/authelia/commit/b8985b57b70acdff8f204ed426ff619e763461ad"
    }
  ],
  "schema_version": "1.7.5",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:P",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Authelia Missing Username Canonicalization in Basic Auth (LDAP)"
}