Hono, a web framework, prior to version 4.6.5 is vulnerable to bypass of cross-site request forgery (CSRF) middleware by a request without Content-Type header. Although the CSRF middleware verifies the Content-Type Header, Hono always considers a request without a Content-Type header to be safe. This can allow an attacker to bypass CSRF protection implemented with Hono CSRF middleware. Version 4.6.5 fixes this issue.