@@ -1,8 +1,18 @@
 import { MessageSend } from '#/entities/message'
 
+function sanitizeFilename(originalName: string): string {
+	const name = (originalName ?? '').trim()
+	if (!name) return 'file'
+
+	const lastSlash = Math.max(name.lastIndexOf('/'), name.lastIndexOf('\\'))
+	const base = lastSlash >= 0 ? name.slice(lastSlash + 1) : name
+
+	return base.split('?')[0] || 'file'
+}
+
 export function formDataHelper(file: File, dataForSend: MessageSend<any>): FormData {
 	const FD = new FormData()
-	FD.append('file', file)
+	FD.append('file', file, sanitizeFilename(file.name))
 	FD.append('info', JSON.stringify(dataForSend.info))
 	FD.append('content', JSON.stringify(dataForSend.content))