Undici's cookie header not cleared on cross-origin redirect in fetch
ImpactUndici clears Authorization headers on cross-origin redirects, but does not clear `Cookie` headers. By design, `cookie` headers are [forbidden request headers](https://fetch.spec.whatwg.org/#forbidden-request-header), disallowing them to be set in `RequestInit.headers` in browser environments. Since Undici handles headers more liberally than the specification, there was a disconnect from the assumptions the spec made, and Undici's implementation of fetch.As such this may lead to accidental leakage of cookie to a 3rd-party site or a malicious attacker who can control the redirection target (ie. an open redirector) to leak the cookie to the 3rd party site.PatchesThis was patched in [e041de359221ebeae04c469e8aff4145764e6d76](https://github.com/nodejs/undici/commit/e041de359221ebeae04c469e8aff4145764e6d76), which is included in version 5.26.2.