CVE-2026-8162: multiparty vulnerable to Denial of Service via Uncaught Exception in filename* parameter parsing

multiparty@4.2.3 and lower versions are vulnerable to denial of service via uncaught exception. By sending a multipart/form-data request with a Content-Disposition: filename*=utf-8'' header containing a malformed percent-encoding (e.g., %FF, %GG), the parser invokes decodeURI on the value without try/catch. The resulting URIError propagates as an uncaught exception and crashes the process. Any service accepting multipart uploads via multiparty is affected.