OAuth2feil

OAuth2feil is a term used in Norwegian-language discussions to describe errors that occur during OAuth 2.0 authorization flows. The concept corresponds to the errors defined for OAuth 2.0 by the standards and is commonly encountered when clients interact with authorization servers and token endpoints.

Errors in OAuth2feil can arise at two main points in the flow. At the authorization endpoint, the authorization server may redirect the user-agent back to the client with error information included in the redirect URL query parameters, often along with the state parameter. At the token endpoint, the client exchanges an authorization grant for an access token and the server responds with an error payload if the request is invalid.

Common OAuth2feil codes include:

- invalid_request: missing or malformed request parameters.

- unauthorized_client: the client is not authorized to request a token.

- access_denied: the user or server denied access.

- unsupported_response_type: the server does not support the requested response type.

- invalid_scope: the requested scope is invalid or not allowed.

- server_error: the authorization server encountered an unexpected condition.

- temporarily_unavailable: the server is overloaded or down for maintenance.

For the token endpoint, additional codes can appear, such as invalid_client, invalid_grant, unsupported_grant_type, and invalid_scope. Error responses typically include an error parameter and may include error_description and error_uri to provide more details, with state used to protect against cross-site request forgery.

Best practices for handling OAuth2feil include validating inputs, ensuring redirect URIs are pre-registered and match exactly, using PKCE for public clients, avoiding leakage of sensitive information in error messages, and logging errors for diagnostics while preserving user privacy. See also OAuth 2.0 and RFC 6749.