CVE-2025-71381 Hono - Vary Header Injection in CORS Middleware

Hono before 4.10.2 fixed in 4.10.3 contains a flaw in its CORS middleware: when the origin is not set to "", the middleware copies the Vary header from the incoming request into the response. Because Vary is a response header that should be managed by the server, an attacker can supply arbitrary...