{"cve":"CVE-2026-47203","nvd":{"published":"2026-06-19T21:16:57.253","modified":"2026-06-23T16:06:25.397","status":"Deferred","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.","cvss_v4":{"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","score":2.9},"cvss_v3":null,"cwes":["CWE-178","CWE-307"],"references":["https://github.com/authelia/authelia/commit/b8985b57b70acdff8f204ed426ff619e763461ad","https://github.com/authelia/authelia/security/advisories/GHSA-hjj4-hfjm-fmrj"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:39:28.638635428+00:00"},"epss":{"cve":"CVE-2026-47203","score":0.00453,"percentile":0.39326,"date":"2026-11-01"},"kev":null,"osv":[{"id":"GHSA-hjj4-hfjm-fmrj","url":"https://osv.dev/vulnerability/GHSA-hjj4-hfjm-fmrj","summary":"Authelia Missing Username Canonicalization in Basic Auth (LDAP)","modified":"2026-06-26T21:45:24.295336600Z","packages":[{"ecosystem":"Go","name":"github.com/authelia/authelia/v4","purl":"pkg:golang/github.com/authelia/authelia/v4","ranges":[">=4.38.0 <4.39.20"],"fixed":["4.39.20"]}]},{"id":"GO-2026-5430","url":"https://osv.dev/vulnerability/GO-2026-5430","summary":"Authelia Missing Username Canonicalization in Basic Auth (LDAP) in github.com/authelia/authelia","modified":"2026-06-25T23:01:13.400245007Z","packages":[{"ecosystem":"Go","name":"github.com/authelia/authelia","purl":"pkg:golang/github.com/authelia/authelia","ranges":["all versions"],"fixed":[]},{"ecosystem":"Go","name":"github.com/authelia/authelia/v4","purl":"pkg:golang/github.com/authelia/authelia/v4","ranges":[">=4.38.0 <4.39.20"],"fixed":["4.39.20"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}