CVE-2026-69215: Http4s: CookieJar middleware matches by substring, leaking cookies cross-origin

The CookieJar client middleware decides whether to attach a cookie to an outgoing request using an unanchored substring test on the host and path, instead of the domain match specified by RFC6265 5.1.3. A cookie stored for example.com is therefore sent to any host whose name merely contains example.com (e.g. evilexample.com), leaking potentially sensitive cookies to an attacker-chosen host.