GHSA-6HQ5-7373-42RG PHPSpreadsheet: SSRF bypass via HTTP redirect in WEBSERVICE() domain whitelist

Summary The domain whitelist introduced in PhpSpreadsheet 5.4.0 for the WEBSERVICE formula function can be bypassed via HTTP redirect. The whitelist validates only the initial URL's hostname, but filegetcontents follows 302/301 redirects by default without re-validating the redirect target agains...