{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-47203","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","state":"PUBLISHED","assignerShortName":"GitHub_M","dateReserved":"2026-05-18T22:07:37.436Z","datePublished":"2026-06-19T20:19:47.903Z","dateUpdated":"2026-06-22T18:13:48.660Z"},"containers":{"cna":{"title":"Authelia Missing Username Canonicalization in Basic Auth (LDAP)","problemTypes":[{"descriptions":[{"cweId":"CWE-178","lang":"en","description":"CWE-178: Improper Handling of Case Sensitivity","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-307","lang":"en","description":"CWE-307: Improper Restriction of Excessive Authentication Attempts","type":"CWE"}]}],"metrics":[{"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"HIGH","attackRequirements":"PRESENT","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"LOW","vulnIntegrityImpact":"NONE","vulnAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":2.9,"baseSeverity":"LOW","vectorString":"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"}}],"references":[{"name":"https://github.com/authelia/authelia/security/advisories/GHSA-hjj4-hfjm-fmrj","tags":["x_refsource_CONFIRM"],"url":"https://github.com/authelia/authelia/security/advisories/GHSA-hjj4-hfjm-fmrj"},{"name":"https://github.com/authelia/authelia/commit/b8985b57b70acdff8f204ed426ff619e763461ad","tags":["x_refsource_MISC"],"url":"https://github.com/authelia/authelia/commit/b8985b57b70acdff8f204ed426ff619e763461ad"}],"affected":[{"vendor":"authelia","product":"authelia","versions":[{"version":">= 4.38.0, < 4.39.20","status":"affected"}]}],"providerMetadata":{"orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","shortName":"GitHub_M","dateUpdated":"2026-06-19T20:19:47.903Z"},"descriptions":[{"lang":"en","value":"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."}],"source":{"advisory":"GHSA-hjj4-hfjm-fmrj","discovery":"UNKNOWN"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-06-22T17:29:23.539472Z","id":"CVE-2026-47203","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-06-22T18:13:48.660Z"}}]}}