Affected: Apache Software Foundation Apache Wicket

ResourceIsolationRequestCycleListener protects a Wicket application against cross-site request forgery by rejecting requests that a resource isolation policy judges to come from another origin. Its default policy, FetchMetadataResourceIsolationPolicy, was derived from a reference implementation written to guard static resources, and it inherited two allowances that are unsafe when the thing being guarded is an action on a page: * Every "simple top-level navigation" was allowed. Any GET request carrying Sec-Fetch-Mode: navigate whose Sec-Fetch-Dest was neither object nor embed was allowed, whatever Sec-Fetch-Site said — including cross-site. Wicket invokes component listeners (Link.onClick(), form submits, behaviour callbacks) through ordinary GET navigations, so a page under an attacker's control could navigate the victim's browser to a listener URL and have that listener run inside the victim's authenticated session. Browsers send SameSite=Lax cookies — the effective default when no SameSite attribute is set — on cross-site top-level GET navigations, so the victim's session cookie accompanied the request. * Sec-Fetch-Site: same-site was allowed unconditionally. That value means the same registrable domain and scheme but a different origin — another subdomain or another port. Any sibling origin could therefore invoke any listener by any method, POST form submits included, and cookies are always sent on same-site requests regardless of SameSite. A hostile sibling origin…