Office Open Xml Download Verified May 2026

// 3. Main document part - STREAMING XML (no DOM) var docEntry = archive.CreateEntry("word/document.xml"); using (var docStream = docEntry.Open()) using (var xmlWriter = XmlWriter.Create(docStream, new XmlWriterSettings Indent = true )) xmlWriter.WriteStartDocument(); xmlWriter.WriteStartElement("w:document", "http://schemas.openxmlformats.org/wordprocessingml/2006/main"); xmlWriter.WriteStartElement("w:body"); // Title paragraph xmlWriter.WriteStartElement("w:p"); xmlWriter.WriteStartElement("w:r"); xmlWriter.WriteStartElement("w:t"); xmlWriter.WriteString(title); xmlWriter.WriteEndElement(); // t xmlWriter.WriteEndElement(); // r xmlWriter.WriteEndElement(); // p // Content paragraph (sanitized) var safeContent = System.Security.SecurityElement.Escape(content); xmlWriter.WriteStartElement("w:p"); xmlWriter.WriteStartElement("w:r"); xmlWriter.WriteStartElement("w:t"); xmlWriter.WriteString(safeContent); xmlWriter.WriteEndElement(); xmlWriter.WriteEndElement(); xmlWriter.WriteEndElement(); xmlWriter.WriteEndElement(); // body xmlWriter.WriteEndElement(); // document xmlWriter.WriteEndDocument();

stream.Position = 0; return File(stream, "application/vnd.openxmlformats-officedocument.wordprocessingml.document", "report.docx"); office open xml download

XmlReaderSettings settings = new XmlReaderSettings(); settings.DtdProcessing = DtdProcessing.Prohibit; settings.XmlResolver = null; A malicious .docx upload (if your system re-uploads user files) may contain a document.xml compressed from 1 KB to 1 GB inflated. When your server processes it for download generation, memory is exhausted. !DOCTYPE doc [ &lt

<!DOCTYPE doc [ <!ENTITY xxe SYSTEM "file:///etc/passwd"> ]> <w:p><w:r><w:t>&xxe;</w:t></w:r></w:p> Always disable external entities and DTDs in your XML parser. !ENTITY xxe SYSTEM "file:///etc/passwd"&gt

Set a maximum decompression ratio (e.g., ZipFile.Extract with ExtractEntry limits). For generation, do not decompress untrusted archives. 4.3 Path Traversal in ZIP Entries Evil entries like ../../config/secret.xml inside a ZIP can overwrite files.