CVE-2026-47203

The record

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.

Affected packages

Related vulnerabilities

• CVE-2026-86472 fast-uri is a dependency-free RFC 3986 URI parser for Node.js, used by Fastify and ajv. CWE-178
• CVE-2026-87876 Two case-insensitive comparisons on request-derived usernames outside the main… CWE-178
• CVE-2026-84428 fastify versions before 5.12.2 implement the case-insensitive nature of HTTP header names… CWE-178
• CVE-2026-84303 gRPC-Go is the Go language implementation of gRPC. CWE-178
• CVE-2026-83612 xmldom is a pure JavaScript W3C standard-based (XML DOM Level 2 Core) DOMParser and… CWE-178
• CVE-2026-73270 Improper Handling of Case Sensitivity vulnerability in Erlang/OTP inets httpd allows a… CWE-178
• CVE-2026-82726 Permissive Regular Expression vulnerability in ash-project ash_phoenix lets a remote… CWE-178
• CVE-2026-78959 Improper handling of case sensitivity in FileSystem in Google Chrome prior to… CWE-178