Authelia Missing Username Canonicalization in Basic Auth (LDAP)_CVE-2026-47203

{
    "lastseen": "",
    "description": "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.",
    "published": "2026-06-19T20:19:47.903Z",
    "modified": "2026-06-19T20:19:47.903Z",
    "type": "cve",
    "title": "Authelia Missing Username Canonicalization in Basic Auth (LDAP)",
    "source": "GitHub_M",
    "references": "https://github.com/authelia/authelia/security/advisories/GHSA-hjj4-hfjm-fmrj\nhttps://github.com/authelia/authelia/commit/b8985b57b70acdff8f204ed426ff619e763461ad",
    "id": "CVE-2026-47203",
    "bulletinFamily": "",
    "cwe": [
        "CWE-178",
        "CWE-307"
    ],
    "cvelist": null,
    "sourceData": "authelia authelia >= 4.38.0, < 4.39.20",
    "sourceHref": "",
    "cvss": {
        "score": 2.9,
        "severity": "LOW",
        "vector": "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",
        "version": "4.0"
    },
    "cvss2": [],
    "cvss3": {
        "version": "",
        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
            "baseSeverity": "",
            "attackVector": "",
            "attackComplexity": "",
            "privilegesRequired": "",
            "userInteraction": "",
            "scope": "",
            "confidentialityImpact": "",
            "integrityImpact": "",
            "availabilityImpact": ""
        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "authelia",
    "version": ">= 4.38.0, < 4.39.20",
    "vendor": "authelia",
    "ai_description": "",
    "ai_severity": "",
    "ai_vendor": "",
    "ai_product": "",
    "ai_version": "",
    "ai_score": 0
}